It's about money. The movie industry, the tourism industry, the martial arts training industry.. they'd all be heavily affected if Chinese martial arts were suddenly shown to be just a gimmick, especially if the person proving a point was in-fact Chinese.
It's about power and respect, which in China (and everywhere else) translates to one's ability to make money. "Don't rock the boat". When so much seniority has been earned by so many people, naturally they'll try to maintain their place.