I really hate this argument. They get free education, room and board, meals, stipends. Basically there is very little they have to pay for out of pocket. Then they have a shot at a multi million dollar career if they are good enough. When they are done, even if they didn't make the pros, many walk into cushy high paying jobs because of their name and the school they played for.
The big problem is that they never discuss the sports outside of football and basketball. If they start paying that pie will be split between all sports, mens and womens, across 14 schools. The pie starts to shrink a lot at that point. Then they will start arguing over if the QB should get more than a swimmer. Will they then want a pay scale based on how that type of stuff and how will it affect facility upkeep. Could they start a trust for each athlete based on how much they bring in, but then womens golf would receive next to nothing while whoever's jersey number is for sale gets the pot. Would jealousy come up from the 3rd string LB not getting as much money as the first string QB? At what point do they start getting agents to negotiate for them to the highest bidder. When there is money agents will start flocking to be involved. 5 star gets more than 3 star on payment scale? Just to many rules and regulations to go through and put in place for this to ever even work. They would probably still complain after that.