China can be a threat for American global domination, but in the very long run the USA probably have better prospects. I think the most significant of the mentioned problems of China is it's demographics. Now Chinese population is 4 times larger than that of the USA (and still USA is a superpower while China is not), but by 2100 according to projections that I've seen, this ratio will be closer to 2.5:1. United States will be able to maintain population growth and relatively high share of working age population through immigration, while Chinese population will be increasingly more aged and after several decades will start to shrink. And many areas of China seem to be overpopulated already, so even if Chinese fertility rate will rise to 2+ or China will attract enough migrants from another countries, Chinese populations have relatively little room for growth without causing significant harm for economy and environment.
On the other hand, China have its advantages. For example, Chinese students perform extremely strong in PISA and other tests that measure academic performance: http://en.wikipedia.org/wiki/PISA#China (all East Asian nations show high scores, but Chinese results seem to be especially high, considering that most part of China still belongs to the third world). If it is a real sign of exceptional level of Chinese education, China will be able to compensate decreasing numbers of working force with its high quality in the future.
In the future population growth will be a problem, not an asset. Underestimating how fundamental this change is going to be is a big mistake.
And yes, China will likely be able to achieve a very high technological level, which will be crucial. The biggest threat to the US is a decline in its educational system. In the future it wont be so easy to attract high skilled people from other countries, since opportunities will be better elsewhere. So you will have to stop wasting so many talents among disadvantaged Americans and the anti-intellectual culture in large parts of the population (and the Republican party) has to decline.
