Let me add a few on the key differentiator: Innovative power

The advantage of countries like China is cheap labor and low production cost. The advantage of USA is its vitality of innovation. Look at last 30 years, it's a parade of non-stop technological innovations that invented and re-invented the entire industry structure of this country. Why countries like China can't become an innovative power as powerful as the US? it's the complete social order that suppresses innovative ideas to be capitalized as efficiently as in the US. For example, in Silicon Valley, a young guy with his buddies can easily convince a VC to infuse a million dollar to start his own company, then IPO that into the broad market for more capitalization. Some people think that US is full of low IQ and fat white guys knowing nothing about algebra, I would say he doesn't really understand USA's advantage. The real advantage that USA enjoys is its ultra efficiency in capitalizing and usage of human intelligence, regardless it's from an Indian's brain or a Jew's brain. It doesn't have discrimination towards innovations.

What US has is exactly what China is missing. It's also what Japan is missing. The VC system has oiled the US so efficiently that every 10 year will spawn a new innovation, be it internet, be it Google, be it CDO financing. All of these innovations will be used to milk the cream from its "tenant" economy.

The "tenants" are simply happy too. They enjoy the fruition from such rapid innovation cycle.

Why USA has weakened a bit since the 90s? partly due to its temporary lull in its innovative cycle. I bet the next one will soon arrive, complete reinventing itself again, creating millions of highly paid knowledge jobs.