I think they risk implosion before achieving anything like monetary or military hegemony. They're stretched awfully thin now. China is a nation of disparate ethnic elements forcefully glued together. Here in the US our sense of history lasts about fifteen minutes. In other parts of the world they think in terms of centuries and even longer. Without trying to stir up a current controversy, when we here in the West think of the Chinese picking on Tibet, they might remember when Tibet was picking on them. But to put it another way - lots and lots of promising Chinese students are sent to the US to study. Even back when it was party policy to preach annihilation of the West, the children of their dictators were living right around here, eating American food, studying in American schools, making friends just like everyone else. It's all a very complex fluid dynamic.