The NFL is the most profitable sports league in history, yet people can't wait to declare the end of football.

Among the first to present a cogent argument for such a downfall were two economists, Tyler Cowen and Kevin Grier, writing for Grantland in February of 2012. They imagined a slippery slope lubricated with lawsuits and liability, culminating in "a lot less money in the sport, and at first it's 'the next hockey' and then it's 'the next rugby,' and finally the franchises start to shutter." That spring, national CBS columnist Gregg Doyel offered a similar prediction, declaring "the NFL is finished." Roughly a year later, Ryan Van Bibber, the NFL editor at SBNation, stopped short of this endgame, writing "The [NFL] could turn into more a niche sport with a small, passionate audience." The most recent figure to portend the NFL's demise was Mark Cuban, who called the NFL "10 years away from implosion," before going on to say something about pigs, hogs, and animal cruelty.

According to the most recent Forbes rankings, 30 of the top 50 richest sports teams are in the NFL, highlighting the league's unprecedented financial dominance. As far as we know, every team makes money. The NFL's annual revenue of $9 billion is greater than the GDPs of many small countries. The NFL is really, really big, and nowadays, anytime something is called big, someone responds, "Too big?," puts on their sunglasses, and strolls into a supernova. We're fascinated with how big, rich, successful things fall -- and even more fascinated when they don't.

There's no reason to believe the NFL has peaked, except our own intuitive sense of how big things can get before they burst. But that hasn't stopped some people from suggesting the NFL's crash has already begun. Cuban's prediction and similar prophecies tend to identify a symptom or cause, then break out their Jump to Conclusions mat. The appeal to our collective intuition that big, successful things can't stay big and successful forever does half the work for them.

But how likely are the various theories prophesying the death of the NFL? I consulted with experts to find out if football's decline has already begun.

1. The NFL will oversaturate the market.

This is the theory to which Cuban subscribes. It's a slippery slope argument, since by Cuban's own admission, the NFL's current strategy of expanding Thursday night games is "perfect." But over time, the thinking goes, the NFL will continue to expand into all days of the week, desensitizing the American public to the league's spectacle and resulting in an overall decline.

This season, the NFL is experimenting with a Sunday morning game, moving the start time of a London game to 1:30 p.m. local time, or 9:30 a.m. Eastern, giving fans roughly 15 hours of nonstop football if they choose to indulge. Cuban sees these types of expansions, or more permanent second windows on Thursdays and Mondays, as potential pitfalls.

Still, to suggest this might be bad for the NFL is pure conjecture. University of Michigan sports economist Rodney Fort told me there's no data to suggest the NFL is in danger of oversaturating the market. Ratings are better than ever. There's simply no evidence people are tiring of football.

Moreover, it's a curious argument, considering that the NFL has by far the fewest live games of any major sports league. Each baseball team plays for roughly 486 hours every regular season; with most games televised, that's something like 14,580 hours of baseball broadcast live each season (each game has two broadcasts, one in each local market). By contrast, each NFL team plays about 48 hours of football every regular season -- about 10 percent of a baseball season. Yet the NFL is in danger of oversaturating the market?

It would be one thing if there was some kind of historic precedent, a once-mighty sports league you could point to where this has happened. But there isn't. Sports have declined and risen in popularity over the years, but none mainly because of market saturation.

Will this happen? No.

2. Television will change and the NFL will somehow be left out of the loop.

In a subsequent Facebook post, Cuban delved deeper into his NFL doomsday scenarios. One in particular was novel and intriguing:

"TV is changing. Not near as much as people think. TV subscriptions started climbing again this past quarter as Cable and Satellite distributors greatly improved their user interfaces, VOD, internet streaming and discovery. But could it change? Yes it could. Could we see more streaming and less traditional delivery? Maybe. Will that have an impact on the NFL which is one of the few programs that has so many viewers of a live program that they could be seriously and negatively impacted if streaming became the expectation for sports and tv programming? Yes. If the NFL needed to stream its games over the public internet in a net neutrality world, thats [sic] a problem for the NFL."

Cuban's arguing that if people are watching games via the internet, the multi-billion dollar TV deals might not continue to come the NFL's way. Yet, as Cuban admits, live sports are pretty much the only thing networks still have to draw viewers. With popular shows now watched on-demand via any number of methods, live viewing is mandatory only for sports and the occasional mega-event like the Oscars. "Sports are going to basically be the only thing networks have that can't be time-shifted and watched whenever you want to watch it," University of Alberta sports economist Brad Humphreys said. Cuban's supply and demand curves here are backwards: Since live sports are one of the only remaining sources of serious advertisement revenue, networks will only increase their bids.

As for the growth of streaming, as Humphreys told me, "The leagues ultimately control the broadcast rights to their events. Finding a way to get those events in front of more eyeballs is going to increase revenues, not decrease it." The more convenient it is to watch the sport, the more ads can be sold. Just because streaming feeds currently feature fewer ads doesn't mean they always will; as more people stream Sunday Night Football on NBCSports.com, NBC will further monetize that traffic.

What Cuban may be envisioning here is a cultural shift where watching games live stops being the norm, much like the shift we have seen with scripted programming. But this seems farfetched -- the communal aspect of sports is one of their primary appeals. And you almost literally have to hide under a rock to avoid the results of a game you plan to watch later. (It seems quaint to watch a 20-year-old Seinfeld episode where Jerry need only not answer the phone or listen to his messages in order to watch a Mets game on delay. You'd have to burn your cell phone and wear the blast shield Luke Skywalker dons in order to have a chance of not having a game ruined today.)

Will this happen? Not only will it not happen, it makes no sense.

3. A rival league will usurp the NFL's popularity.

Don't laugh, people!

"I think we're sort of overdue for a rival league formation," Humphreys said. This was the only scenario to which he did not audibly scoff. "I would not be surprised to see that happen." In his view, with which Fort generally agreed, the main hindrance to previous rivals was a lack of financial might and willingness to absorb losses in the early stages. But there are plenty of American billionaires. What if a few of them took a few hundred million out of their mattresses and pooled it together?

In a Facebook post announcing his purchase of the virtual reality company Oculus VR, Mark Zuckerberg, one of those aforementioned billionaires, explicitly set his sights on sports:

"Imagine enjoying a court side [sic] seat at a game, studying in a classroom of students and teachers all over the world or consulting with a doctor face-to-face -- just by putting on goggles in your home."

Suppose that, when the time comes for Facebook to expand this technology into the sports world, Ted Turner convinces Zuckerberg that, rather than sell this unique technology to sports leagues, they could create their own league and profit off that, rather than sell the rights to broadcast through virtual reality.

According to Fort, rival leagues need three things in order to have a chance of succeeding: 1) At least one megalopolis to make most of the league's money and support smaller cities; 2) a TV deal; and 3) some method of competing with the existing league. The NFL has left Los Angeles, the second-largest metropolis in the country, wide open for a rival league to occupy. And if a broadcast mogul such as Turner was involved, Turner Sports could offer the league the required exposure from the very beginning. Facebook's unique VR technology could provide a market advantage few rivals could offer.

In order to be a true rival, the new league would have to hold a rival draft as well, competing with the NFL for players. With billionaires backing the project, it's conceivable they could offer more money than the NFL's rookie salary structure does and lure players away. There's some precedent for this: Before their merger, the AFL and NFL were constantly battling for players, so the scrappy newcomer American Football League held its draft prior to the NFL's.

One significant problem with the rival league argument is that it assumes the NFL will remain motionless while a new league laps them in every competitive aspect. More likely, though, the NFL would instead innovate and adopt whatever measures the Turnerberg Football League, if you will, was using to succeed. "There's nothing stopping [the NFL] from responding strategically to any form whatsoever of intrusion," as Fort said.

Even if, somehow, a rival league became popular and legitimately competed with the NFL, they wouldn't destroy it. "The endgame is a merger," Humphreys observed. "That's the only endgame there's ever been in the economic history of professional sports in America."

Will this happen? It's remotely, distantly possible, but the NFL isn't going anywhere. It might just have a new name.

4. Concussions

There are two theories about how this could come to pass. One involves crippling litigation that will bankrupt the league. The other predicts a dwindling talent base as young athletes seek out safer sports. Of course, they're not at all mutually exclusive, but it's easier to consider them individually.

Litigation relating to head trauma will financially cripple the NFL.

This is the short-term scenario, the metaphorical killer punch. High profile lawsuits, such as the judge-rejected $765 million settlement with more than 4,500 retired players, have only increased speculation about the final costs of head trauma litigation and whether the NFL can absorb it. 

The NFL's main concern is not really a mass settlement like the one that was rejected by Judge Brody, but a series of individual lawsuits. Every player has the option to opt out of the settlement and launch their own suit, creating a stream of former players suing the league. I spoke with Professor Michael McCann, Director of the University of New Hampshire's Sports and Entertainment Law Institute and frequent contributor to Sports Illustrated, about the potential ramifications of these opt-outs. "The worry for the NFL is that in the years to come, players start to do this and it just becomes a world of continuous litigation over concussions. It may not be bankrupting litigation. The NFL may be able to settle these cases, but it will be costly."

The NFL's other option is to not settle and eventually take one of the cases to court. According to McCann, there are a number of defenses the NFL could employ if they chose to argue the case. The collective bargaining agreements between the players union and league could be seen as an agreement on the league's safety protocols, mitigating the players' arguments of negligence. Further, illustrating direct causation could be difficult in court.

Even if the NFL thinks they could win a suit on such grounds, though, it still might not want to go to court, given the amount of information it would have to disclose. Anyone who saw or read League of Denial can imagine the skeletons in the NFL's closet. Even if the court ruled in the NFL's favor, they might suffer irreparable public opinion damage. (Imagine the spectacle of a crippled, brain-damaged veteran getting cross-examined by high-priced NFL lawyers.) Beyond the head trauma issue, the NFL would likely have to surrender financial information never before disclosed, whivh could indirectly cost the NFL billions in public subsidies for sports stadiums and tax breaks.

"The league may just continue to settle these cases and hope they're dismissed early," McCann said. Consistently fending off lawsuits is nothing new for the NFL; McCann offered the comparison to the NFL's intellectual property litigation, which seems to crop up every few years. (Remember NFL vs. American Needle?)

If the NFL did go down this road, they could almost certainly afford it. Roger Goodell has publicly stated the NFL's goal of $25 billion in annual revenues by 2027, which isn't as crazy as it might sound. Any settlements would likely be payouts over time rather than a lump sum, so it's hard to imagine the amounts would be massive enough to ruin the NFL. "It may be paying a significant amount, maybe it's hundreds of millions or tens of millions, it's hard to know specifically," McCann predicts. "But I don't think it's going to be billions of dollars a year."

Will this happen? About the same chance as the Jaguars winning the Super Bowl.

Concerns over head trauma will disastrously erode football's talent pool and/or fanbase.

The theory here is that, as a result of health concerns, parents will push their kids to play other sports. The NFL will experience a gradual decline as the best American athletes and youth interest gravitate elsewhere.

Unlike previous theories, there's some data to back this up. Pop Warner saw a 9.5 percent drop in participation between 2010 and 2012 -- right when the concussion issue reached popular prominence -- leading some to assume the trend is already underway. But fewer kids playing football doesn't necessarily mean the quality of play will decline. When discussing this question, Professor Humphreys used the labor economics term 'compensating differential': "The salaries are large enough to offset the risks the employees take." As of now, the NFL has an adequate compensating differential: We don't see many NFL players walking away because of concussion concerns. Athletes still consider it worth their while.

You can see how this logic will influence our interpretation of the Pop Warner participation statistics above. The kids who care the least about football, or who just plain stink, will stop playing because the risk isn't worth it to them. But the kids who have the slightest potential for a future in the NFL are far less likely to give up the sport. They will ignore or accept the risk in the face of a potentially lucrative career. "I think psychologists would say it's optimism bias," observes McCann, "the idea that we're able to recognize there's a general risk but for irrational reasons believe it's less relevant to us."

What we're more likely to see is a tightening of safety protocols at the youth, high school and perhaps even collegiate level. Increased safety protocols at local games, such as mandatory concussion specialists on scene, ambulances on-call, or modern protective gear could prove prohibitively costly for some youth programs or parents unwilling to shoulder the costs. More likely, the cost of insuring football players could skyrocket, ending high school and college programs across the country.

Ultimately, it will come down to community priorities. It's hard to imagine increased costs will stop southern cities that build $60 million high school stadiums from playing organized football -- and those are the communities that are far more likely to produce star football players anyway. The combination of cost and concern may lead to the game being shunned by some communities and geographic areas, though, which is precisely what the NFL doesn't want.

Smoking, a traditionally accepted activity suddenly realized as potentially fatal, provides an apt precedent for such a shift. In 2011, according to the CDC, 19 percent of American adults were cigarette smokers, down from 42.4 percent in 1965, or from about two out of five adults to one out of five. But the regional differences in smoking habits tell the real story: In 2012, the Midwest and the South had far more adult smokers (26 percent and 19.7 percent, respectively) than the Northeast and West (16.5 and 14.2 percent). Particularly when comparing those geographic breakdowns with average annual income (Excel download), this is the type of trend the NFL wants to avoid -- and has historically dedicated many resources to fighting.

smoking graph

Image via the Center for Disease Control

In 1997, John Seabrook wrote a fascinating article for The New Yorker about the revolution the NFL experienced when it hired Sara Levinson, a former co-president of MTV, to take over the league's marketing. "Football is not 'on trend', as the marketers say," Seabrook wrote. Levinson was hired to reverse the image that players abuse their bodies and minds for a career that lasts on average three and a half years, leaving them crippled and fog-headed. Seabrook described the task at hand:

"People who like to watch the game -- my wife, for example -- tend to enjoy the ballet part of it: the perfect passes, the circus catches, the great breakaway runs. (She thinks that tackling should be banned from the sport, and that the pros should play flag football.) But my experience of playing organized football is that the essence of the game is hitting, not ballet. Especially if, like me, you weren't fast or agile, the way to excel at football was to hit people as hard as you could on every play. It was fun to run a "counter" (a misdirection play), in which I was the pulling blocker -- to ram full speed into the blind side of some dumb lineman who had bought the fake, empty my body into his body, and knock him flat. But to be hit, that made you wonder. Suddenly there is impact, the solid thwunk of someone else's body smashing into yours, followed by a silence except for your own strangled-sounding "unnngh." You are flying through the air, not knowing yet what hit you; your head strikes the ground first, and a weird, smoky smell comes into your nose. You lie on the ground moving your head cautiously, because the impact has obviously torn your brain free from the webbing that connects it to the inside of your skull. Then you see your opponent standing over you, laughing at you, or maybe snarling at you -- it's hard to be sure. This is the least upbeat but perhaps most immutable aspect of football, and it's something that Levinson will have trouble selling: football is about hard work, pain, and losing."

This puts all the NFL's rule changes to limit contact and highlight offensive skill over the last two decades into perspective, while foreshadowing the upcoming struggle against head injuries. Starting in 1997, the NFL produced an internal report titled "Game Plan 1997" which focused on the importance of youth:

"Nothing can be more important than how we manage young people (particularly ages 6-11 … ) into our fan continuum and begin to migrate them toward becoming avid/committed fans.

Critical Action: Generate early interest and enthusiasm. Transform/convert their casual interest into commitment. Amplify to avidity.

How?: Elevate/personalize players; Football education. … Increase N.F.L. intersection with pop culture/trends; Continue to give them products that allow them to build and express their loyalty."

Despite sounding like some sort of Boy Scout/Silicon Valley hybrid, this strategy would prove a massive success. As described by author Michael Oriard in Brand NFL: Making and Selling America's Favorite Sport, Levinson launched "Play Football" targeting kids aged 6-15 with all types of consumer doodads, instructional clinics and flag football programs "to turn kids into NFL consumers." From 1994 to 1999, participation in flag football programs grew from 350,000 to 5 million. Those children are now adults with incomes.

After Levinson's departure in 2000, the NFL merged all branding, licensing and marketing under one umbrella, expanding the scope of NFL Properties, and named Roger Goodell head of the department. His subsequent promotion to commissioner highlights how important the league considers this side of their operations.

This history is why the CDC smoking graph likely alarms Goodell. While the talent probably won't go elsewhere, the money might. The NFL is the most profitable sports league in the world because of all the young fans it has managed to incubate and hatch into jersey-buying, Sunday Ticket-subscribing, Coors Light-drinking superfans. The league revolves around 100 million-plus people watching football every Sunday, and it has spent untold millions to cultivate a strong young fanbase and embed football into America's youth culture.

If football can't shake its bloodsport reputation, and children no longer play, the NFL will undo much of the progress made over the last two decades. The league is doing everything it can to counteract this trend with its Play 60 initiative and heads-up tackling training programs. But if playing football is going the way of smoking, then the NFL's decline is already underway.

Will this happen? This is a very real threat to the NFL as a cultural mainstay -- but it isn't an imminent demise. It's a generation or two away.

5. Whatever happened to boxing will happen to the NFL.

On the surface, the demise of boxing seems like an apt analogue to the NFL's current state. Once upon a time, boxing was easily one of the most popular sports in America, perhaps even the most popular. Don Majeski, longtime matchmaker and boxing agent, illustrated this over the phone with statistics from his copies of Ring Record Books and Encyclopedia: In 1945, 540,000 people attended 43 shows at Madison Square Garden, out-drawing many baseball franchises that year. Today, boxing barely exists in the American sporting consciousness.

The similarities between boxing at its height and the NFL make it seem like a perfect comparison: Extremely popular sports largely centered on the spectacle of violence, which sparked a public outcry over said violence and a slow response by the powers of each sport.

The problem is, very few experts believe boxing declined in popularity due to its violent nature. This offers a tidy excuse for what was, in reality, a complex cultural shift, largely due to the sport's lack of organization and its economic short-sightedness. In addition to Majeski, Eric Bottjer, a matchmaker for over twenty years, emphasized to me that there were no easy answers for boxing's decline.

Among the factors mentioned by both Majeski and Bottjer were the failure to commodify television broadcasts in any meaningful way, and an insular culture among the matchmakers and promoters who became wholly self-interested once revenue streams dried up, maximizing pay for each fight with no eye to the future of the sport. In blatant money-grabbing moves, sanctioning bodies divided championships so severely that there are now 17 weight classes and four world champions in each weight class, resulting in 68 boxing champions every year. "The base appeal of boxing is: who is the best fistfighter on the planet?" Bottjer said. "Nobody knows [the champions] now because the sanctioning bodies have been permitted to do what they want. They've diluted the quality. The business is built now for the best athletes to avoid each other."

"It's erosion," Bottjer summarized. "It wasn't just one factor."

Boxing's decline was a complex process very few people saw coming until it was already underway. By the time it was evident, the sport lacked the organization to do anything about it.

This, more than anything else, is why boxing's decline offers very few lessons for the NFL. If there are two things at which the NFL excels, it's the rising-tide-lifts-all-boats coordination and masterful commodification of television broadcasts. In fact, in its earliest days, the NFL experienced some of the problems boxing couldn't handle, but in response the league instituted revenue sharing and a reverse draft -- becoming the first sport to do so -- and overcame them.

Will it happen? What happened to boxing did happen to the NFL, in some ways. But instead of cannibalizing their own business, teams banded together and largely invented the structure of the modern sports league we all know today.

So how could the NFL decline?

"I'd take a pretty hefty bet from anybody who wants to put their money on the demise of the NFL in ten years," Professor Fort said. But he did leave room for one possibility, which strikes me as the most plausible: raw stupidity. "Economists are prone to think nobody makes mistakes and it's a frictionless place," said Fort. "But there's nothing that prevents collective stupidity."

It's hard to know what such a misstep might look like. Perhaps the NFL miscalculates and decides to take a head trauma lawsuit to trial, irrevocably turning public opinion against it. Perhaps they accept a TV deal valuing cash-in-hand versus exposure, where the streaming rights packages are mismanaged and, in a changing tide of viewership habits, the league becomes harder to watch.

Perhaps some combination of the above scenarios, combined with a few poor decisions, could exacerbate one another until everything irreparably fails. But there will be no one thing that kills the NFL -- if anything kills it at all.