My goodness, it's amazing how people get all hysterical.
Flag football can both be increasingly popular and have absolutely no impact on the top levels of tackle football (and I say that as someone that won't be letting his son play tackle football in high school... as he actually got a concussion this year in FLAG football).
Look at the top 100 most watched TV shows of 2022:
https://www.si.com/extra-mustard/2023/01...en-ratings
82 of the 100 most watched TV shows last year were NFL games.
5 more were college football games.
This means 87 of the 100 most watched TV shows were football games.
Meanwhile, not a single scripted TV program was on that list.
Football is MORE powerful in our culture than ever. It is literally the ONE thing that Americans still almost universally watch (which wasn't the case even in 2010).
As a result, top athletes will continue to play football because that's the where the money is (and that's accelerating). Those top athletes are the ones that matter for the continued performance of NFL football and top level college football. Whether the more "casual players" stop playing football doesn't really matter at that front - the overall participation rate in football is less relevant than whether *top* athletes are still participating in football (and I don't see a slowdown on that front at all).
(And note that a misperception that I often see on this forum is that somehow the North will watch football less than people in the South because their kids aren't playing football. That's simply not true. When you look at the NFL, which dwarfs the viewership of college football, it's the *Northern* markets that dominate - Chicago, Philadelphia, Boston, Pittsburgh, Milwaukee, etc. High school football participation rates in those markets have pretty much zero correlation with the TV viewership of football in those same markets. We ALL want to WATCH football whether we'd let our kids play or not.)