In 2024, 171 countries had birth rates below replacement rates. That's gotten worse since then. 70% of people live in countries with birth rates below replacement rates.

So not just a handful of countries.

It’s a handful of countries that have 1) “really, really low birthrates,” i.e., not just below replacement but very below replacement AND 2) do not have relatively permissive immigration policies.

That most countries are 3) below replacement rate by some amount is a separate third thing.