Earlier quoted context omitted.
Exactly. If you think about it, most species reproduce when resources are abundant, and stop reproducing when resources become scarce. That's basically what is happening to young people here.
It's the opposite with humans. 3rd world/developing countries have extremely high birth rates. The best mechanism for "population control" in people is to improve a population's standard of living.
The reason for this may be that, in the absence of public social safety net, family (and particularly close family) serve as a safety net, and particularly children, once they are able to be productive, can be a kind of safety net against infirmity for their parents.