My prediction is that, if large swaths of China and India get Internet connectivity, they, or their internet providers, will have to choose between

* NATted IPv4 connectivity (maybe with one IP per city and not one per household) and

* buggy but non-NATted IPv6 connectivity.

with the former being cheaper to implement. Most likely, IPv6 will only see universal adoption after the old gear that has buggy or too-slow IPv6 support has been thrown out. Then again, if a large government (say, China) puts itself behind IPv6 (say, because having one IP address per citizen is more convenient for keeping tabs on everyone), a fast transition would be more likely.

Don't get me wrong here: I think that the transition to IPv6 will happen eventually, but not as fast as the shrinking number of remaining IPv4 address blocks would suggest.