To the comment above, I have 21-year-old son and a 10-year-old son. The difference in the parents' attitudes toward letting their boys play football between those two ages has been remarkable. My 21-year-old had 2 tackle football teams for his private North Dallas elementary school by 3rd grade back in 2011 or so. My 10-year-old son, they can barely field a flag team. I think 3 kids started playing tackle independently in 5th grade this year but no team of school kids was formed. I'll be surprised if there are more than about 15 kids (out of around 60 boys versus I think my older son's class had about 40-45 out of 60 boys) who come out for 7th-grade tackle football in a couple of years.
I know North Dallas private schools are NOT the most fertile of recruiting grounds but participation levels are declining elsewhere I'll bet.