Im fairly certain its not that simple.
Alot of MMA fans become UFC fans because of the loss of interest. And some MMA fans just arnt as excited anymore cause they have been watching the sport for a long time.
I don't understand that concept at all. Many of the European fans here have been soccer fans forever and I never hear about them losing interest in soccer. Same for me and American Football. Love it as much as ever and will never get tired of it. That's how I am with MMA as well, especially now that there is more talent out there then ever before and more media outlets covering MMA then ever before. I got to watch Bellator, RFA and UFC all in HD on my TV without paying any extras over the weekend. 3 free cards. If anything the interest should be growing with the talent. Plenty of great fights happening all the time. Who gets tired of knockouts, back and forth battles and amazing displays of skill and effort? Love it. Love it, love it, love it.