When the sport enjoyed a surge of general interest in the mid- to late aughts, it had to do with compelling athletes and compelling fights. People didn't become fans because of some accidental exposure to the sport, as such; they became fans because they were exposed to rivalries like Chuck Liddell vs. Randy Couture, or because they saw an incredible highlight reel of Anderson Silva knockouts online, or because they heard that pro wrestler Brock Lesnar was going to try his hand at a real fight.
For a lot of reasons—the aging of a generation of stars, the promotion's habit of running down its own fighters, and bad luck, among others—the UFC, even though it runs some great shows from time to time, doesn't have those kinds of broadly compelling athletes or fights on offer right now. What it does have is its #brand, and a Rovellian faith in it—a belief that you can't run too many shows, that fighting is destined to be the biggest sport in the world, and that if you can get people to watch a UFC card, any card, you'll make some new fans.