Gman, he was fighting guys that were his size. The Undertaker is 6'8", 285 pounds, with agility and power. Yes Bruce Lee was great, but giving up 140 pounds? Sorry, he'd get pounded. I know wrestling is fake, but it still requires strength and agility---and unlike that Kung Fu man dancing thing pro wrestling moves can be incorporated into a street fight.
Do you think Bruce Lee could beat up Brock Lesner? It'd be like a duel between a jeep and a tank- eventually the tank will catch him with one shot, and it's all over.