The one child policy really gonna be up there with killing all the sparrows long term...

It was in place 45 years and only gone a decade.

You can't just flip a cultural switch and expect them to become bunnies overnight. And that's not even getting into the economic part.

Kids are fucking expensive.

When workers aren't paid well, people stop having kids. That shrinks labor supply in a generation, workers can command enough pay to have kids, and population will stabilize.

The wealthy hate populations dropping, because they have the luxury to plan ahead and know eventually it leads to more powerful workers.

It's why it's a constant boogeyman and reproduction has been prioritized thru virtually all of recorded human history.