There are a bunch of demographic reasons why we should expect America's dominance to end. If all citizens were equally productive, we'd expect the U.S. to be n

There are a bunch of demographic reasons why we should expect America's dominance to end. If all citizens were equally productive, we'd expect the U.S. to be no more than 5% of the global economy, and China and India to be roughly 4x as large. Plus the population pyramid in the U.S. is about to invert, with more dependent seniors than productive wage-earners. Corporate profits, economic data, geopolitical stability can all flip quite quickly (just look at Germany in 1914, per grandparent poster) - demographics is the one factor that is relatively stable.