Didn't we just see this article about Japan in oh, say 1987? This is like the perennial "The Great Depression of the 1990's" book. Sure, it could happen, if everything went right for China and everything went wrong for the United States.
However, one trip to Hong Kong or Shanghai and Chan will not be very happy back on his Manchurian farm with his $20.00 a week standard of living. If China wants to run with the big dogs, its gonna have to feed its pack and that will be increasingly expensive.
In my estimation, a country that supports free enterprise, curbs taxation on entrepreneurship and supports higher education will always be a pitri dish for success. If China can do that, great. If not, then don't count on China sailing forward trouble free for long.
As a business owner let me assure you the USA is NOT
"a country that supports free enterprise, curbs taxation on entrepreneurship",
taxes are extremely high, and regulations are massive. You can't take a dump without filling out a form and getting government approval. We were once a free people, now we all work for the government.
It's the same article with Japan replaced by China....
I would mostly guess that China and India -- the two big population centers will spend the next century bringing their entire huge populations to a decent standard of living. They won't be a threat.