This...doesn't quite compute to me. Professional football was born out of amateur athletic clubs and college clubs. The lack of a development league for the NFL is lamentable for a few reasons, but I don't think it's insidious that people play for free then get the attention of the NFL, if only because most people play football because they enjoy the sport.

If HS and CFB didn't exist, there would be no NFL, because it would mean that everyone stopped caring about football.

(Disclosure: I live near Pittsburgh; even though I never played, the sport runs deep in the roots of the area!)