I think its more like... why doesn't china have any top-ranked courses YET!
When you look at China as a nation what are they good at? Engineering, math that sort of thing (yes i'm stereotyping, but hear me out). These are both very strict things, they follow rules; 2 + 2 always =s 4 and F is always = MA. So for a nation that is relatively new to golf 18 tees + 18 greens, a clubhouse with some bunkers and water and now you have GOLF.
But as we all know, there is much more to golf than just that. Obviously, they have imported the likes of Jack, Arnold, Norman and all the others that have courses at places like Mission Hills, but what do they have to compare it to? Hirono is across the sea, and how many get to go to Aus? It takes time to really develop the spirit of golf. For me, there are 2 ways to play the game: you can play it like MECHANIC, learning about swing planes, pro-nating, club face angles... that sort of thing. OR you can play like a POET, where rhythm, tempo and balance are key, what was that feeling the golf course thread all about?
So going back to my stereotyped china... once they have played enough golf, and begin to experience what great golf course design is all about, i'm sure it is just a matter of time before they figure out how to engineer a top-ranked golf course and have their own great golf course architects... they are just to smart and clearly love the game to much not to.
With Tom D working on 2 courses (is it still 2?) and C & C with another... all on Hainan Island, top ranked golf in china is sure to come.