Your current wasted demographic dividend is 12 million due to unskilled labor.
And as of china ,if anything that could bring down its economy will be its popuation deceleration.
Secondly, one important factor that we overlook is corruption free govs. See demographic deividend policy works when you have proper regulations and policies not just in place but are implemented effectively. In that way the older population also adds to economy. India had a chance to play around with china's growth rate if india had enough skilled labor cuz china will lose 6million skilled workers in upcoming decade due to old age.
Howelse you think japan progressed. Do countries like india pakistan have such politicians....?????
I will try going though links and if i can discuss in detail i will post in thread again.