Other than, "What do you think about the anthem protests?" the following is by far the question that I have been asked the most during this football season from fans, family members, or talking with the hosts of sports talk radio shows across the country:

"Why is offensive line play so poor across the NFL?"

It's complicated and there are many different reasons, but rather than trying to explain it every time, I thought it made a lot more sense to write it all down so I can just point people in one direction moving forward.

Week 7 was just the latest example of how many more teams are "have nots" as opposed to "haves" along the offensive line around the NFL.

Colts quarterback Jacoby Brissett was sacked a whopping ten times by the Jacksonville Jaguars in a rare home shutout on Sunday. Not exactly incentive for franchise quarterback Andrew Luck to hurry back on the field.

Broncos quarterback Trevor Siemian was likewise running for his life behind an offensive line that not only couldn't block the Chargers front in the pass game but also wasn't able to establish any sort of running game in a 21-0 shutout.

And even though the 49ers, unlike the Colts and Broncos, found a way to score some points, rookie QB CJ Beathard was bruised and battered, resulting in a couple of strip sack fumbles against an average Cowboys pass rush that hounded him throughout the game.

There are countless other examples, but you didn't come here for that. You came here for answers. Here are the four biggest reasons NFL offensive line play isn't as good as it used to be.

1. College spread offenses emphasize speed over technique

Most college programs now run an up-tempo spread offense that attempts to beat the defense more by tiring them out and forcing them to stay vanilla than they do by blocking people with supreme skill. I had one college coach, whose program switched from a more traditional pro set to a college spread offense, tell me recently that they decided "there were just too many plays where spread offenses weren't even blocking anybody yet were still getting yards."

While up tempo offenses include more reps and thus more opportunities to get better for the O-line, it feels like so much of the passing game is so quick and lateral that it doesn't adequately simulate the NFL, even though the pros have certainly been incorporating some college concepts of their own in recent years.

The bottom line is, college players don't have to work to finish and sustain blocks as long because either the ball carrier is past them or the ball is thrown in an instant in these offenses. It stands to reason that if college players were running more of what the pros do like they used to it would help linemen develop.

2. Practice makes perfect, so less of it doesn't help

The "wins" for the NFL players in the latest Collective Bargaining Agreement (CBA) signed in 2011 included significantly reduced practice time, both padded and otherwise. This one's not real complicated. If you practice less you aren't going to get as proficient. That goes for both each individual's technique as well as the familiarity and continuity between linemates, which absolutely matters for a position group that needs to be in sync and work in concert with each other so often.

It's a major factor without a solution, because it's hard to believe these changes would ever be rolled back and that NFL players would actually begin to practice or hit more moving forward.

3. Defenses have evolved

As recently as 2007, you could still see many defensive units that wouldn't make sure they had four quality pass rushers on the field every time it was a likely passing situation. The Giants and their famed "NASCAR" package that helped them knockoff the undefeated Patriots in the Super Bowl XLII changed all that. Now teams recognize how vital it is that any rusher on the field in those situations is a guy that has a legitimate chance to get 5-plus sacks on the season, and is thus a real threat for the offensive line.

Plus, advanced analytics have helped to dissect protections even more, allowing defenses to have an even better chance of exotic blitzes getting home against the quarterback. That, combined with the inexperience of young players out of college going against those crazy blitzes means more sacks.

4. It's a numbers game, in many ways

Look at any metric or trend over the last five years and you will notice two things; the NFL is getting younger and teams are throwing the ball more. Not exactly an ideal combination for offensive lines across the league. It's a position where a lot of players don't really come into their own or master their craft until their mid-to-late 20s, yet the league average age is below that. Younger is not better in turns of craftsmanship, and when you combine that with more and more passes, it is a recipe that is bound to fail or at least be worse than it used to be. Which it is.

All of that is not to say you can't have a good offensive line. Many teams, including the Eagles, Redskins, Titans, Steelers, Saints and Cowboys, are showing it is possible -- but even some of those units aren't quite what they were a year ago, for various reasons.

Frankly, given all the forces working against them, it's impressive they're able to produce the units that they have.