By the year 2100, Which Country Will be the World's Number 1 Superpower?

[Frodo]

I'm still placing my bet on the United States retaining its status as the world's sole superpower and reigning hegemon for another century, if not longer.  

[Frodo]

We're going to be the world's leading superpower for a lot longer than anyone thinks.  I don't think China any longer has a chance of catching up to the United States as a world superpower, since it appears to be turning into a giant version of 1990s-era Japan.  Once you slip into that trap, it is awfully difficult to get out of it, especially given adverse demographics compounded by China's self-inflicted one-child policy.

Russia is in terminal decline, which Putin has done nothing to arrest despite his efforts.  

Which leaves India, and it is unclear if they have the desire or willpower.  

[Frodo]

We're going to be the world's leading superpower for a lot longer than anyone thinks.  I don't think China any longer has a chance of catching up to the United States as a world superpower, since it appears to be turning into a giant version of 1990s-era Japan.  Once you slip into that trap, it is awfully difficult to get out of it, especially given adverse demographics compounded by China's self-inflicted one-child policy.

But unlike Japan, China has a substantially larger population and substantially smaller GDP per capita than the US.  China's so far behind the US in GDP per capita, that even in a pessimistic scenario, it still grows faster than the US, doesn't it?  So it keeps closing the gap on the US, it's just that it'll take a lot longer to reach parity than previously thought possible.

*shrugs*

I suppose it's possible -though by the time (in the distant future) China does catch up in your scenario, wouldn't it have fully transitioned into becoming a liberal, multi-party parliamentary democracy?  This economic crisis could potentially be that trigger starting the process.