People need to understand that demographic trends are not demographic prophecies. They are basically doing a regression with demographic data to state that if this trend continues, the outcome Y will happen after X years. So this is why all these analysis that focus on just one aspect of the whole thing are deemed to fail.

One thing Western pessimists fail to state is that economies are complex systems. So the introduction of different policies over time can make a system re-organize itself. In this case planned economies like China are more able to adapt and change their direction if there are issues, because they can do widespread changes more easily. In capitalism, policies struggle to be put forward because dominant players are always acting as an agent against change, so changes are much more costly sociologically and politically.

So I have to give kudos at Chinese evolution of economic planning. It overcame many issues the old soviet system that was extremely rigid and eventually caused its stagnation. I wish the URSS were able to work out its issues without being balkanized.