again the argument isn't about not making money, it is about retaining amateur status in the NCAA rules.
best example off the top of my head:
Ricky Williams at Texas, was drafted by the Phillies out of highschool and signed a professional contract with them yet he went to Texas to play for the Longhorns. so in the off-season he played single-A and Double-A ball before giving it up going into his senior year. he had a multimillion dollar deal and lost his amateur status as a baseball player but retained his status as an amateur in football. he could not accept a scholarship but rather had to pay his own way through college. the NCAA has no problem with this, but had he of sold his Texas football jersey than he would have been in violation of his NCAA athletic amateur status.
also, Cedric Benson at Texas did the same thing, signing a pro contract with the Padres out of highschool.
if a student athlete was able to legitimately acquire a high paying job then it would be legal, the problem is that outside of pro-baseball there isn't a job around that pays a high-school grad only able to work part-time to part-part-time very much over minimum wage.