Use an analogy that works better then. Like ‘wooden posts’ for kungfu and ‘being black’ for sanshou.
Does what about sanshou show CMAs produce good fighters? It’s existance? No. That someone who does well in sanshou does well in another contest? No. That the best sanshou guy is a good fighter? No. That the average sanshou guy is a good fighter? No. Why? Because we don’t know simply from ‘sanshou’ that the person happens to practice a CMA. As has been pointed out, alot of sanshou people actually happen to train in kickboxing, wrestling, and boxing.
What if a high school wrestler decides he’s really into MAs when he graduates; starts taking boxing lessons and attending a university wrestling club. A few years later he decides he wants to compete, looks around, and decides sanshou is the venue for him. He really works hard boxing and wrestling to prepare himself for this venue, then he starts competing. Some people would have you believe he is a kungfu man, which is clearly ridiculous.
Conversely, take someone graduates high school having never done a martial art. He decides he wants to take one up, and finds a seven star preying mantis school he really likes, and trains there for three years, then decides he wants to compete in sanshou. He works really hard in his mantis class to prepare, and then starts competing. Some people would have you believe he is not a kungfu man, which is clearly ridiculous.
What if we take this same guy, you might ask, only he doesn’t join the preying mantis school, he joins some class called ‘sanshou.’ Well, what do we say about him? We would say the same thing about him as if he took a class called ‘martial arts,’ which is to say it would depend entirely on what he was learning.
Traditionally speaking, sanshou is a term used for a generic training method used to achieve skill as part of most (all?) traditional chinese martial arts - basically equivalent to the term ‘sparring’ in english. Eventually, someone had the idea to get different fighters from far away to fight one another, and charge people to watch; and just like the people who got this idea here called it ‘fighting championship’, over there they ended up calling it ‘sanshou.’ The specific rules and culture caught on over here, and kept the same name, and now we have all this confusion.
Some people/school/classes call themselves ‘sanshou.’ In my mind, this is very similar to some people/school/classes calling themselves ‘MMA’ - in both cases it’s a label that arose to describe someone training with a specific tournament format in mind (yeah yeah I know the objection allready; spare me for sake of discussion ;p ). Is it right to say that an MMAist is a wrestler? Well, it very well might be. And on the other hand, sometimes it’s not. Same deal with sanshou and kungfu.