True, if China bans Bitcoin or ICO will affect a lot to cryptocurrency. But we'll get used to it, do not let the Chinese too much influence to the market when we are too familiar with that.
China may hold 20% global market but Japanese and South Korean have more % from China so it's just a matter of time before bitcoin able reach $ 4000 once again. I'm also read that Chinese government did not shut bitcoin in permanently so I think there will be a chance that China will operate bitcoin but with government regulation