Despite Muai Thai being a staple for striking literature in MMA, there is surprisingly little representation of fighters who used to compete in Muai Thai circuits. A few exceptions would be UFC's Shevchenko (of Kyrgyzstan) and ONE's Dejdamrong (of Thailand). While both of these fighters have gone to live out very decorated careers in their respective organizations, on aggregate, the proportion of former Thai-circuit fighters are very small.
I was thinking maybe it has to do with culture. Even though I would have loved to see Buakaw in his prime versus the likes of Dustin Porier at 155, Buakaw has reportedly likened his training to a spiritual quest and he claims to fight out of the honor of the Thai monarchy.
Save for groups of loyalists, who would remain Muai Thai no matter what, what is likely preventing wider cross-over between Muai Thai circuit fighters from mainstream MMA organizations, like the UFC?