Do you understand that most of the money they get is actually being paid from the advertising hype right? On top of the money, they get from tickets, watchers and partnerships. They should also pay taxes! And in this regards, I think the law should be like the income system for workers... the more you win, the more you should pay. And not something flat like it is (I believe) in Europe.
It would be nice to think it would be possible, but if you check the economics of the "game", you quickly understand why these things move a lot of money.