China will never match the US. They have too huge a population to even begin to clean up the extreme poverty, they don't have anywhere near as varied and plentiful natural resources, they're decades behind on scientific and militaristic technological development, and guess what, the US isn't slowing down at all. Japan will never be anything like they were before WWII. They have a limited economy, although very successful; still, limited. They have no military as the US provides their defense. I don't see any Asian nations rising above the rest to actually compete with the US. China might overtake some western European nations, perhaps.