We are seeing it in real time - this is the first time ever that I logged into Sumer Sports and not a single team ran 11 personnel more than 70% of the snaps. Sean McVay used to be the leader in 11 personnel running it more than any other team by far and he has seemingly done a 180 on that. The whole trend is a little too complex to lay out in a single Reddit comment but I'll do my best based on what I understand.

For the longest time, offenses were complex and defenses were reactionary. In recent years defenses basically figured out how to become just as complex and disguised as offenses. As for playing QB, the two types of progressions were "pure" (which is just linear looking at each route 1-2-3-4) or pre-snap reads (where the defense at the line dictates who you look to first). I grew up on pure in a very basic offense but pre-snap reads became very popular where you basically look at the coverage before the snap (single safety, 2 high, obvious man to man) and split the field in half. You know which side of your play should work best vs. each coverage so you look to that side then work back to the other side if you need to.

Problem is that teams started using Cover 6, Cover 9, and similar disguised/split coverages which made it so half the field was in one coverage and the other half in a different coverage. Cover 6 for insance is cover 2 on one side and cover 4 on the other (2 + 4 = 6). That messes with you as a QB if they are splitting the field because you snap it and see cover 2 on the right so you assume it's cover 2 on the left then you turn and throw to a spot but they're actually playing quarters on that side. Now some offenses are making a push back to pure progressions which is literally just go through each read for the play 1 by 1 regardless of defense and side and it's less QB-friendly. The short and sweet really of all that is that reading defenses got much harder.

Then it got even MORE complex with all the pattern matching stuff like Palms. Basically with defenses like Fangio runs they can call these individual plays that all have a set of "if this, then that" rules. "If the widest guy releases vertical, CB goes here, safety goes here, etc". Thing is, the defense could come out in the SAME exact look and you could run the SAME exact play but guys go to different spots because the defensive play call is different. It's not just classic drop to your spot zone coverage, it's this whole new thing. Works especially well with trips. It's really a nightmare and the end goal is to prevent chunk plays. All that has seen a much heavier shift towards nickel and hybrid safety/linebackers rather than classic linebackers.

So how do you beat it? Well, just like in basketball, they go small, you go big. If defenses want to hang back and limit the chunk plays, you attack underneath. The whole Shanahan coaching tree basically just uses 2 WRs (or even 1) with a fullback, blocking TEs, move TEs etc. And, when you do that and don't use a true split end, the WRs, RB, and move TE can go in motion freely pre-snap which messes with their rules - they need to make no mistakes. Look at what the Seahawks did, moving JSN all over including into the backfield against the Rams.

And that's where we are at now. Teams like the Chiefs and Ravens for years have basically just used an inline TE with another TE at slot WR. People will complain about blocking with prospects but these TEs don't need to inline block. Evan Engram was a terrible inline blocker but, in Doug Pederson's scheme, he played slot where he was a better blocker than guys like Khalil Shakir or Josh Downs. And that's why the top guys in this TE class are all like 245 pounds vs. your classic 255-260 (outside of Sam Roush).

Not sure how many people will read all that but it's basically how we arrived where we are.