You touch on some realities, but it may also be the case that the general pool of players and potential players is just smaller--and getting smaller every year. To be honest, if my sons were at an age where they would be starting to play organized sports I doubt I'd encourage or even allow them to play football (because of what we now know about brain injuries). I know that makes me something of a hypocrite since I still follow and love the game. But I think more and more parents are feeling that way.
If there's one high school coach in the area who's been out in front about the brain injury situation, it's Infante. I don't mean to suggest he's been doing it for selfish reasons, i.e. to help him with recruiting, but his leadership in the area might be reassuring to some parents.
Also, if you take a look at the teams from SJP and Wood--and, to some extent, LaSalle too--you'll notice that there's a much higher proportion of African-American players than there was, say, ten years ago. (I wonder if there is any PCL school where the proportion isn't at least a bit higher.) There are probably several reasons for this (including, I would say, a change in the demographics of who is and isn't starting to play football at age 10 or 12). Some coaches have been better than others in leading / relating to this new mix of players. I'm not suggesting that some coaches are closet racists, but there are all kinds of changes--including some that have nothing to do with race, like the ways kids now use social media--that mean that what may have worked 10 or 15 years ago probably doesn't work so well.