One must realize that MMA encompasses Muay Thai along with BJJ, boxing wrestling, and a bunch of other techniques.
Being good at one dicipline doesn’t make you the best fighter. There’s nobody in that sport, that’s any good I should say, that is only a master of one style.
You have to be adept at either using or defending against all types of fighters. How many times has TJ fought people with Lesnar’s particular skills?
I know that Brock has been trained to a degree in Muay Thai, as well as any other fighting style that would come up. It’s part of training for all kinds of fighters.
That’s the dif between stuff like that, learning the Muay Thai and stuff, your goal is to be the best in that style. Your goal in MMA training is to beat the opponent, not just be the best you can be.