If he can get a hold of Conor before getting cracked then yeah, but it's not that easy and the people acting like it is are retarded. Watch Askren's fight where he kept failing TD's and couldn't get the clinch and ending up eye poking the guy to Bolivia. Being desperate for TD's like that and reaching for your opponent from a distance can be very dangerous, especially against someone as good as Conor is on the feet. Every fight starts on the feet and Conor is just a different level in that aspect then basicallly everybody around right now.
He takes advantage of very very small openings and opportunities. Conor catching Askren on the way in wouldn't be a surprise and it's the same way in a possible match with Khabib. Most people can't even get their hands on Conor because he cracks them first. Mendes did it because he's actually got good striking and is very fast/explosive. Askren has zero stand up and Khabib's stand up only seems affective when opponents are at the fence, which he uses just to get TD's or initiate clinch.
Don't count Conor out just because we've seen him struggle on the mat in the past. Conor is known for ending guys in seconds. Counting him out against anybody at all is just stupid. Not saying Conor would win, just that he has a very high chance. He can end it right away with one shot because of his timing and accuracy. Very few can capitalize on such small openings like him. He could very well catch Askren coming in, same with Khabib. I'd be more confident in Askren winning than Khabib though 'cause he doesn't need the cage to complete TD's, he gets them from everywhere. Stylistically a very tough match for Conor, but still very winnable.