It has nothing to do with real life.
Without even looking, I'm going to bet that you've got a decently (but not hugely) successful low or mid DI team that's had some high scoring players that are quite good for your level but definitely not as good as the stronger starters in the BCS conferences. As such, they put up big scoring numbers against lesser competition, but simply aren't good enough to get drafted.
This is not a David Blaine HD trick ... all of the AA teams are highly populated with these guys, just take a look. In real life, these players would not earn AA honors. It's one of the little HD foibles that they will, provided their team is reasonably successful.
So honestly, instead of lamenting the fact that they're not getting drafted, I'd consider yourself very lucky that they're getting the AA mention in the first place.