In a perfect world, yes. But you'd be naive to think that these guys are always in a position to go to class and have time to study. A lot of schools' football players probably get very lenient treatment so it's not like a 20 year old kid is just gonna go to class 12-15 hours a week, study for another 10-20 hours, and still practice and work out how ever many hours they do when they're having administrators give them a playful pat on the arse and telling them to just focus on their "dreams" and they'll make it to the big time.
On top of this, there are probably some situations where the kids are pressured into not even doing anything academic because the corrupt administrators think that'll take valuable field time away from them.