China still has many challenges to overcome and its eventual hegemony is not a forgone conclusion yet. For one thing China will very likely have a massive currency crisis in the coming years. While most currencies float against each other with a little bit of fixing by the goverment China has been artificially lowing their currancy vs the USD for a long long time, and the lower the USD goes the more expensive it is. At this point China foreign reserves are a liability, they have so many dollars that tehy can't actually sell them all off anymore, they don't know what to do with it and they can't afford to keep fixing their currancy as the company develops.