Comparing this to NASCAR is apples and oranges. NASCAR is on a much bigger level than the UFC, and the sponsors involved are generally much larger companies.
MMA is big, but it's not going be raking in the really big Madison avenue sponsors anytime soon. It's still seen as a violent sport, and Dana White does not help the matter. This idea of using the 360 degree contracts will only drive fighters away in the end.
The UFC can still dominate Vegas, just like fighting and gambling have for decades in that city. They will do good on PPV, sometimes better than others, just like it's been, but these moves to try and generate more revenue at the expense of hurting the fighters will backfire on them. Why rock the boat?
One of two things can ultimately come from this. If they start signing all their fighters to highly restrictive deals, and they continue to make money and gain popularity, the fighters will likely revolt, and we could see the formation of a union, which is doubtful but still not out of the question. Or, it will end up going the way of boxing were the sports top stars consider themselves individual entities and just won't sign with the UFC unless they get their way.