Reasons:
1) injuries
2) year round practices/workouts
3) kids can play so many other sports today
I played in the 1970s. Today I’m fine, no health related conditions, probably in better shape than 95% of people my age cause I played a lot of sports in high school & still workout pretty good 5 days a week. Not sure if I’d have the discipline to do that if I’d blown on a horn my high school life. That said, today’s football is year round at most schools, spring ball, summer workouts, 7 on 7, etc. who has time for a job to make alittle $, play another sport, just be a kid, etc. A lot of different ways for kids to go today.
Both of my sons played into high school but moved on to baseball exclusively cause football was such a time demand and their future was baseball.