Headlines, headlines, read all about it...
It's all about the headlines and the drama they can put behind it. If the name carries you, ride it! Even if a no name beats a big name, in a convincing fashion, I'm sure their next fight negotiations would be substantially adjusted.
As for UFC paying poorly, it's capitalism in the USA babe! The owners know they have a good thing going. The fighters need the UFC more than the owners need them (at least for now). There is no other mma sport in the USA that can offer a fighter this type of return for what they love to do. That's why so many are looking to other countries for their big payday if the UFC doesn't oblige. Plus you may hear about the BJs and Pulvers that walked away with contract disputes as a contributing factor.