Why don't more TCMA guys enter more MMA events? Certainly in this country limited opportunity, especially the lack of any kind of decent amateur circuit. This makes it very difficult to break into. If your first competitive match is going to be at a semi-pro event it's somewhat off-putting (if you can even get on the card).
Of the amateur events that are around in this country, too many of them are geared towards Gi styles and make you wear one (so this costs you extra, and you have to fight in an uncomfortable, unfamiliar outfit), have stupid rules about striking (I won't fight in a stand up event that doesn't allow face punching, I'm certainly not going to do an MMA fight thus hamstrung), or are about pushing an association agenda (I once tried to enter a supposedly "open" event, only to find that their "open" event required you to have association mambership, at $120!!!)
If I could find a safe, well run open amateur event I would have no hesitation in taking my students there, but they seem to be few and far between.
As for why TMAists don't do better? A) think about it, why doesn't someone who trains in a TMA not beat someone in a sporting format when their opponent trains solely for that sporting format? B) really the track record isn't as bad as it would appear. The vast majority of TMAists (indeed stand up fighters) in the early UFCs were either has beens or nobodies, fighting guys at the top of their games such as Gracie, Shamrock, Taktarov etc.
As for why doesn't some master jump in and fight for the honour of TMA? Largely because the term master implies that you're somewhat over 20, and have a little perspective on things