You're volunteering your football/sports talents to improve the brand/image of the university just like any student is volunteering their time/effort/grades to increase program rankings future applications/interest in that school. And really, only 25-30 athletic departments actually turn a profit each year, how would that effect the smaller teams - tennis, soccer, etc. Do they get a piece of the pie? What about your 3rd string linebacker - what's his compensation? How do you measure his contribution and "sacrifice" for the almighty football squad? It's not like each and every single school is going gangbusters.