In 1977, there were 1,074,973 high school students playing 11 man football and 28 NFL teams in a country on 220 million. In 2015–16 there were 1,083,288 playing and 32 NFL teams in a country of 323 million.
With the echo of the baby boom past its demographic peak, the numbers will shrink below the 1977 numbers(which had peak baby boom cohorts of 1960–61.) So the number of elite talent will shrink, hence football will get worse. This isn’t even accounting the numbers of kids being withdrawn by parents for safety concerns.