Buakaw would destroy mayweather or pacquiao in a no rules fight. Muay thai / kickboxing should be huge in the u.s. but it's not big at all. I know the reason, there isn't enough fight camps or gyms in the united states, the most gyms for stand up are probably in california but other than that there are very few camps/gyms.
Apples to oranges my friend. A few buddies that train Muay Thai sparred with Buakaw in the Toronto area a few years back... he's a beast for his size.
Of course he'd beat Mayweather or Pacquiao in a K1 or Muay Thai fight. But likewise, you put him in a strict boxing fight with these guys and he'd get walked on.
No denying talent buy you can't compare the sports just like that.
R.I.P. PRIDE FC
Jon Jones . Travis Browne . Demian Maia. Cain Velasquez. Fabricio Werdum