[fakethenews2022]

No you didn't: "What’s really the downside of falling birth rates (as long as they stabilize, and they obviously will)?"

There is no way the population stabilizes unless the birth rate increases to replacement rate. The birthrate is WAY, WAY below replacement rate.

Also, why assume that something will stabilize? That assumption seems not rooted on any evidence.

[eldritch_4ier]

I said they obviously will stabilize. They always do. Everything always does. At a certain point the population is just so low that having children becomes highly advantageous again. There's very very few biological system where the entire population just dies out from lack of reproduction (despite all other resources to do so being available).

On the other hand: there is absolutely 0 evidence to suggest that the population wouldn't stabilize. There are sub populations of humans that already have stabilized populations, this is true throughout the animal kingdom. If it's just preferences to not have kids, then those people will see their genetic line stopped and the people with preferences to have kids will see their genes dominate. If it's environmental, then our path will look a lot like that of other animals experiencing environmental shifts: certainly tough, but if you can adapt fast enough you'll be ok.

Right now, the main reason people don't have kids who want them is finances. The likely outcome here looks like the economy will winnow as a consequence until having kids becomes a positive financial decision (and that might mean going back as far as subsistence living in a worst case scenario). Regardless, the population will stabilize short of an asteroid or other catastrophe.

There's not a single precedent ever for what you suggest. The population stabilizing is the default for all of nature.

[fakethenews2022]

There actually is an example of a human subpopulation that will go extinct due to not reproducing: https://en.wikipedia.org/wiki/Sabbathday_Lake_Shaker_Village

Your argument about sub populations can be just as easily applied to humans as a whole. Perhaps humans will be replaced by another species.

If you look at nature more coarsely, you don’t see population stabilization. Instead you see speciation and extinction due to random and constant changes. Perhaps there will be an environmental event that we would otherwise survive that will do us in because of our low population.