Somrak was an outstanding fighter, not sure why he was never given a shot at the titles but he was certainly deserving of getting a shot. Not the first time I've heard that reasoning. "best of his generation" is debatable though.
Promoters don't like overly dominant champions since they're bad for gambling. Dieselnoi, who was the most dominant champion of the previous generation, was stripped of all his belts and forced into retirement after beating every available contenders multiple times.
Sounds like he achieved being the best in his weight class at one point, but I have yet to see evidence he was "the best of his generation," especially considering the 90s had so many beasts.
1) He wasn't denied a title fight just one time, he could never fight for a belt his whole career. And don't tell me he wasn't popular enough. He was a star in his country because of his achievements in boxing (and still is).
2) Greatness is usually defined by how many belts you've won and who you beat, I agree. But when the promoters of the 2 biggest stadiums all think "we can't let this guy fight our champions; he'd beat them all and they'd never get their belts back", wouldn't you say that, in their mind, he was the better fighter?
3) He fought in the Golden Era of muay thay, fought everyone in his prime, fought until he was 40 year olds and his final record is 291 wins, 13 losses, 1 draw. That's the best record I've ever seen.
4) In all the videos of his fights (except those recorded when he was already in his thirties), he is clearly the better fighter. Here is Somrak against Boonlai, a multiple-time Lumpinee champion:
You might wonder: if he is this good then how come he's not high on the list OP posted? First of all, the number of fighters asked is very low. Second of all, we don't know whether fighters are ranked based on ability or accomplishments (in the latter case, Somrak wouldn't even make the top 100 since he's never won a belt). Third of all, as somebody pointed out, asking fighters who they consider the best fighters is the same as asking them who they admired growing up or who they fought and became friends with. Fourth of all, Apidej is not even on the list at all even though he was awarded the title of "Fighter of the Century" by the king of Thailand himself and Samart (who is the widely considered #1 pound-for-pound) does have Apidej in his top 3.
You'll always be able to nitpick when it comes to old school muay thai because of the lack of footage and documentation. The question is: given the limited information we do have, what's the most logical stance to take?
So how would YOU rate Somrak? A good fighter that might have been a great fighter but we'll never know for sure? If that's what you think, then fine but the promoters and gamblers at the time didn't agree with you and his record speaks otherwise.