The idea of a single global culture is a pretty dark path, historically speaking. It is a utopian concept that assumes there is a path that can be followed in order to pursue a more perfect mankind. It stems from the belief that ambiguity and difference are negative forces, to be eliminated instead of embraced.
I think the argument is that the darker historical paths were 'simulation' where 'emulation' would be a better model. The difference (from what I could tell) being that the underlying mechanism of cultural change are copied, instead of just the effects. It could be argued that this is already taking place - the massive reach of the internet is expanding so that more people are being influenced by the same information streams. Internet culture makes the assumption, predictably, that internet culture is good/best. But what if that isn't true? What about those who don't fit into the 'internet' cultural norms?
The author talks of of making subjective judgements about the optimal performance of certain cultures. That's a bit problematic. What about the cultures that are not "optimal performers"? What is optimal? Those who work the most hours? Those who laugh the most? Those who have the least number of fistfights? Those with the greatest GDP?