Right now many cultures still believe in large families. The church still preaches "go forth and multiply". Big business wants more consumers.

After the European plagues passed there was an economic boom - there were fewer people and work for them all. I do not suggest introducing a plague - we need a world wide cultural shift to smaller families.

Of course the human species is poor at preventing problems so we will have a severe crisis before anything positive happens.

I used to watch those collapse of civilization movies and think nothing like this could ever happen. Now I don't know.