Excellent article - thanks for posting.
The beginning of Bernstein's 4 Pillars talks about the last 300 years - how we had the "American Century", before that, the UK ruled the economic world, before that France, and before that China.
The "sun" on each country rose, shined, and then set - with different reasons for the "passing of the economic baton" (military might, innovation, etc).
The "American Century" could be over. Or it could go on for 20 years.
My investments are heavily diversified internationally. I just can't believe that the US can continue with 5% of the world's population consuming over 20% of the world energy and have 50% of the worlds market capitalization.
But who knows....