>>149873020 (OP)Good question.
1. The damage done to longevity is often done in hard sparring training. Western Boxing sparring was/still kinda is brutal and they knock the shit out of each other. Thai sparring is traditionally playful, light and technical.
2. Muay punches are usually not as hard as western boxing punching - you cannot commit to the jab or cross with your front leg out full body rotation like in western boxing. Do that in Thai boxing and your legs or body will get kicked out from under you. Thai boxing punches are often more like an arm punch so less damaging to the brain.
3. Emphasis on kicks means fewer strikes to the head and more to the leg and body.
CTE is absolutely still a thing in Thai boxing dont get me wrong. It is all about how sensibly you spar though.