Khabib can do it once, but that doesn't mean he can do it twice. You have to take into account he's getting pummeled by Conor. If Khabib is having to continuously drag or try to drag Conor down it's not going to look good for him.
As for his clinch, he's long, strong, flexible and has great balance. He's actually very good at sprawling with his hand usage and particularly his quick feet and hips too, and looks even better in the clinch when he isn't as likely to be countered off balance with a shot. He's so slippery and almost effortlessly counters into control, and proceeds to generally attack and break. He doesn't utilize it as much as he could, because he doesn't have to. That means he isn't going to have a ton of finishes in the clinch which people generally use for a basis of skill there, but he wins practically every clinch exchange and he's always making sure he does some damage there before he does break.
Conor's grappling is very underrated. He's actually a pretty good grappler, he has some particular holes in his grappling, but what he does well, he does well.