[mym1990]

A decade(s) of poor leadership in an era of fast moving technology will do that!

[throw_pm23]

That may be the case, but a simple reversion to the mean may also be sufficient explanation. If everyone plays in a globalised (more or less) even playing field, then sooner or later they catch up and the initial lead will matter less.

[mym1990]

Its likely both, no one stays on top of the world forever, and globalization did well to level some playing fields!