It is quite annoying how the UFC always see a contract out before considering pay increases.
So, a dude on a $5000 per fight, 5 fight deal, will contractually make exactly that, regardless of performance. If he's completely shite, the UFC will cut him before the deal is up, thats for sure. But if hes awesome, the UFC dont give a shit. He'll fight for 5 grand for 5 fights, no matter. ( As far as contracts are concerned, anyway )
Every other sport is willing to rip up contracts for improved deals if a dude is doing really well. Shit, in footie/soccer, Ive seen 5 year deals, signed a few months earlier, get torn up and improved because the player is kicking arse.
This is the main reason why having a single MMA organization is bad. The UFC have no fear of a fighter agreeing better terms with a competitor. There are no competitors. They know they can calmly wait till a deal is up, comfortable in the knowledge that they haven't been talking with anybody else about a better deal.
Having said all the above, I do genuinely believe that Dana and the brothers LOVE the sport. I'm convinced any fighter putting on a good fight will always be rewarded by these guys no matter what it says on the official pay figures. Just don't expect an improved contract till your current one is done.