So I think we'd need to define what "works" means in that context. They always fulfill some sort of social/societal function.
Ok, but what "works" depends on the context, doesn't it? I'd argue that, for ex., modern mma exists because of the introduction of new successful techniques. China's sheer size meant that techniques and styles were varied, based on the conditions and most importantly on the way people actually fought. One can argue that the flowery techniques seen in some mas aren't functional nowadays in competition. But, how did the people who invented them fight?
Btw, I think it perfectly reasonable to argue that, like today, the flowery forms weren't the way people actually fought each other, or at least it didn't look that way. I totally agree that in terms of a competition, what works is what's most useful and efficient. Both competitors will be trying to do that. A muay thai thigh kick will work, as will a rear naked, or a slam, or a punch in the face.
Personally, I'd say that anyone who wants to compete needs to study those areasl --because that's what they're going to face, not because one is superior to the other. And, imho, the results are going to look very similar. If a tcc/xy/bg guy goes to the UFC, I bet we won't say he looks like he's doing tcc. Oh, it might be possible to say "look he used a yun shou."
Afa in China's history, what martial art were soldiers trained in?