NBA G-League is a professional league players can join beginning at age 18. The problem is it is more competitive as you have players who are borderline NBA players, players who have been drafted by a NBA team but haven't made the 15-man active roster, and local tryouts. There are more D1 universities at which to play, making it easier to get a spot somewhere--but you have to be amateur to play there. Saying there is no opportunity or that the NCAA must provide you that opportunity is false.

The NFL on the other hand only wants the best of the best--not an up and comer who would be sitting on the sidelines or on a practice squad not developing behind the real pros.