First, the heavy socialism in Europe and Japan, which prevents them from growing as fast as the US. Despite defense budgets 1/2 to 1/3 the size of the US's, their working populations are more heavily taxed. This is to support a parasitic government funded sector. It is the US's support of private property rights, and the view that taxes are an infringement on those rights, that has kept growth alive in the US.
Second, as we have seen the decline, of the authoritarian capitalist asian tigers. So shall we see, the decline of China. The secretiveness and corruption, of authoritarian regimes, isn't compatible with the transparency and stability, capitalism requires. Let me expand on that, to make a profit, a capitalist must calculate the costs and the risks. Without transparency and stability calculating the costs and risks can become impossible.
Third, if so many of the Islamic countries weren't sitting on a ocean of oil. Their culture, would have no more clout, than African culture. They are like Spain was with new world gold, when the oil's gone, the power is gone. Most OPEC countries are in hock, if a new economical source of portable power were found(cold fusion), they would all go bankrupt.
. . . but unlikely to run out of it any time soon, it would appear. Cold fusion is, I fear, tin-foil hat stuff . . .
Excellent analysis generally.