You're making a lot of unfounded assumptions here. Nobody in the world expected that China would be in this position 50 years ago. Very few people expected the US to be in the current situation either: a country saddled with debt, with periodic economic crisis, with a shortage of workers, making life very hard for immigrants, with an increasingly unstable political system and unable to solve racial problems that span already more than 200 years. Nowadays every serious analyst of the economic landscape sees that the future seems brighter for China than for the US. Unless the US is able to do a very serious overhaul of its current path, which it doesn't seem able or capable or doing. My opinion is that the US will become a worse Europe: with more money to spend but with a population immersed in third world problems.