A (relatively weak) inherited instinctual desire to procreate aside, people have kids because it improves their personal outcome. Without modern machinery, the work input of kids will improve the family farm's productivity by more than they consume. With high infant mortality, more kids improves the chances that enough will survive to adulthood. Without modern social safety nets, elders would simply starve or die of exposure if grown offspring didn't take care of them. And so on.
Take those motivators away - and replace them with demotivators such as very high child rearing costs - and the birthrate drops. Low sperm counts? If they aren't zero, people will find a way to have kids if they really want them.
It's a great self-regulating mechanism. The planet's population is getting uncomfortably high, so the birthrate drops. Great.
While the city I live in hardly looks like, say, Shanghai, there has been nonstop residential construction here in all the decades I've lived here. Does this have to be normal? Do cities have to expand until they fill the planet completely? Obviously not. Of course it's going to suck when "peak infrastructure" exceeds the population but not as much as an infinitely growing population would.
this is probably my inner uptopian leftist speaking but -
robots. And the fact that a large amount of the work doesn't actually need to get done.
So long we keep enough skilled tradesmen and farmers, which is not that many with increases in automation, we'll still have enough food, shelter and clothing. Being able to spread that work out amongst more people because bullshit jobs aren't a thing anymore will also probably help, as will changes in lifestyle that enable people to stay healthy longer.
We really don't need a new H&M collection every two weeks, or a new sport jersey every two seconds, or to keep making more and more cars/washing machines/TVs... most manufactured goods (including clothing) can last a while, especially in a world where planned obselence is no longer the norm. If population stabilizes, need for construction drops as well. Food/agriculture is already very automated, I'm sure we can continue to find 3% of the population to keep us fed.
I believe most of the work currently done on earth contributes very little to human happiness, and I hope/want to believe that as our ability to do work diminishes with an aging population, the useless stuff will be the first to go.
silly example, but with GPT-3/ChatGPT, we can now fire all the influencers and have them go toil as construction workers :P
Take those motivators away - and replace them with demotivators such as very high child rearing costs - and the birthrate drops. Low sperm counts? If they aren't zero, people will find a way to have kids if they really want them.
It's a great self-regulating mechanism. The planet's population is getting uncomfortably high, so the birthrate drops. Great.
While the city I live in hardly looks like, say, Shanghai, there has been nonstop residential construction here in all the decades I've lived here. Does this have to be normal? Do cities have to expand until they fill the planet completely? Obviously not. Of course it's going to suck when "peak infrastructure" exceeds the population but not as much as an infinitely growing population would.