What I like best about the piece comes near the end of the article where the author briefly notes factors that the numbers don't address. One factor that struck me was creativity within a culture.
Numbers can quantify growth, and we see China and India on strong growth paths, just as we once saw with the USSR (if you are old enough to remember "We will bury you") and Japan. Both of those players had periods of remarkable growth, although from a modest starting points, but what these two earlier examples couldn't do was adapt/create/change. They could grasp technology at a given point (and I mean technology in a broader context, not just information technology) and replicate what we and Western Europe had done, but when it came time to adapt or significantly change they could not embrace the systemic ruthlessness of capitalism wherein failed business entities are allowed to die and/or better businesses are allowed to replace existing ones.
To be sure, the U.S. knows how to violate these principles, as recently demonstrated with the bailouts, but we do continue to create and replace on a regular basis. And I believe it is one of our strongest characteristics.
I think the notion of our decline is vastly overstated, and I think it is our creativity that will sustain and renew us so long as we allow the markets to replace failed or obsolete enterprises.
All the best,