of course fighters want to get paid well, but my point is, you don't become a champion and stay that way unless you have a real passion for your work.
mirko got his ass handed to him by 2 fighters that he will not face again any time soon, because he's running away to another fed.
put it this way, when couture got beat by tito or chuck, what was the first burning desire he had? to rectify the situation or at least be given the chance to, because he's a competitor first and foremost.
mirko knows very well that if he came back with the pay cut and rebuilt himself, he would get the high purses again.
by running off to another fed everyone knows (not just people on this board) that it doesn't matter who he fights at dream, the guys at ufc own him.
no passionate champion would leave that hanging over their head.