> Economic growth comes from a large population that spends and innovates.

No it doesn't. Economic growth comes from "doing more with more". WHO does that doesn't matter. It matters for inequality and jobs and a lot of things, but not for economic growth. If skynet kills all Americans and builds 5 million nukes, that will be economic growth.

Exactly, doing more with more requires a large population that spends and innovates.

It is about allocation. It might sound like a heresy, but the "invisible hand" is for a good part a myth. Resource allocation in the hand of just a few is

  a) a hand that indeed tries to hide itself
  b) a hand that cuts of energy to the rest of its body
  c) a dying hand

I would rather have economists in general (not directed at you) think a bit deeper about the unspoken assumptions of their behavioral models, to stop confusing models with laws, and to study humans and groups in a broader sense.