McGregor is easily the biggest star in UFC history. The only other 3 you could put in the same stratosphere of breakthrough mainstream stars are Liddell circa 05-07 before Rampage KO'd him. He was starting to become a really big star.
The other is Brock Lesnar, who had a short run but was huge for about a 3 fight stretch. And the 3rd would be Rousey.
But McGregor's PPV #'s (as well as his rabid Irish fanbase) dwarf all of theirs.
