UFC never had any stars that were bigger than UFC itself. It may seem like it for brief moments due to UFC Marketing. But UFC has and continues to be bigger than any one star. IF Dana/UFC wanted to crush Conor then they would.
That's simply not the case though, at least as far as the PPV business goes. For years and years now (and
again, the sales numbers bear this out), the PPVs only do big numbers when there's a big star taking the spotlight. When the UFC is the biggest brand on the card (say, someone like Aldo or Mighty Mouse headlining), they go right back to doing mediocre numbers because the UFC brand on its own doesn't sell that many PPVs.
Where the UFC brand is probably more healthy is on free TV - and that's a big part of the reason why it can't sell PPVs without stars. People don't need to shell out premium money for PPVs just to see "the UFC" because there's a free UFC card on TV just about every weekend.
And they can't "crush" Conor, even if they wanted to. Again, they can't put that genie back in the bottle. And they sure as hell wouldn't want to risk losing him to Bellator or something.
As for Khabib hypothetically refusing to fight Conor that's a lose-lose for him, DUCY? He doesn't get paid,
and he looks like a coward for not wanting fight Conor.
Incidentally I don't know if fighting Conor is necessarily a walkover for Khabib. If he gets Conor on the ground then it's obviously not going to go well for Conor. But Khabib leads with his face a LOT in the stand up and that's exactly the kind of thing Conor is an expert at capitalising on.