I could be wrong, but think that the Athletic department reimburses the school for the cost of tuition for its scholarship athletes, which is a cost that goes to the bottom line P&L for the sports programs. Someone has to pay for the professors to teach them, the classrooms to teach in, etc.
As I have said previously, lots of schools, big and small, have rejected the whole idea of big time sports programs, e.g., all Div III schools and for the most part Div II, which only give 35 scholarships a year in football. And they seem to fill up their enrollment just fine.
Even at UK, the baseball program splits only about 12 scholarships. For the most part, if you want to play baseball even in the SEC, fine, have at it, just expect to pay some, if not all, of your way through school.
Lets be honest, if Murray or Morehead dropped football, basketball or baseball, or track tomorrow, it might be three weeks before half the students even noticed.
In Europe, where the population is sports crazy in some ways just like our own country, they have a lot of top level club sports, but the schools themselves have very small athletic departments. Thus if you want to be a tennis or golf pro, or track athlete, or soccer player, the universities have nothing to do with it. In high school, you play club rugby or soccer, much like our travel squads, but the high schools don't fool with it much, you are there to learn, not play ball.