There already is such a system in place.
Division 1 - which consists of the big league schools like the big ten who recruit the top-notch players and offer full-ride scholarships.
Division 2 - which offers scholarships.
Division 3 - which does not offer scholarships.
A player needs to prove himself in college because professional football is a whole nuther animal. A college student should remain in amateur status until he makes it to the pros. An athlete in college is not a low-wage worker, not when he is getting a full-ride scholarship worth a $100,000 or more.
Funny, MLB and the NHL offer farm systems as an alternative. The NFL and NBA don't.