I hate it that some kids get "run-off," however, it IS very much like an academic scholarship. If you meet the requirements of an academic scholarship, i.e. GPA, you keep your ride. If you meet the requirements of an athletic scholarship, i.e. helping the team win, you keep your ride. Some coaches wrongfully evaluate a high-schoolers talent and offer them a scholarship only to find out later that they were not capable of contributing at level A. Similarly, some academic institutions will evaluate a kid's intelligence and offer him an academic scholarship only to find out later that the student was not capable of performing academic work at level A.
The only difference between these two scenerio's is that one is objective and one is subjective. That does not make the subjective evaluation any less valid.
Again, I don't like it when kids have to leave a program, but these institutions are trying to make money and if you take money to go to a school then you get an early (and sometimes hard) lesson in business.