Presumably either the countries being emigrating from must be at replacement rate, or themselves declining? Somebody has to be producing the next generation, somewhere..

Yes, which is how it is and I don't see this changing any time soon.

But the point is that the illness of developed nations is having the symptoms treated by infusions of immigrants from countries that don't _yet_ have the same illness. If it's a matter of "as countries develop they have less children", you'd better hope other places of the world stay poor and uneducated.

We will develop solutions by then, ideally.

The "illness" is very simple, in my mind.

As rights for women progress, they choose not to have children. Which makes a lot of sense - having children is risky. The reason women in underdeveloped countries choose to have them is because they have less rights and less autonomy, as well as a worse economy.

If you're poor and require a husband to function, then having children is a huge boon. Not that you have much of a choice - your husband usually chooses. He bears little to no risk to having children, so of course he says yes.

What we cannot do in the West is backtrack on education and equality. It would probably work, yes, but we would literally develop backwards. Our economy relies on women working, our economy relies on education, etc.

So, instead, we should make having children a sweeter deal, rather than pseudo-forcing women to have children. We should offer generous and safe maternity leave, we should offer free childcare, and we should implement universal healthcare to eliminate risks associated with infant care, pregnancy, and postpartum care. We could even make higher-education free, to eliminate risks associated with saving for college.

Basically, women aren't having children because it's incredibly risky for little to no gain. By having children, you are ensuring greater economic hardship, health challenges, and less autonomy. It's a Catch 22 - if you choose to stay home, you have sabotaged your career. If you choose to work, you must pay exorbitant childcare fees.

We should not be surprised that women are opting out.

We have examples of countries with universal healthcare, long maternity leave, economic incentives to have children, and better social safety nets.

They have lower birth rates than the United States. Look at Sweden, Norway, and Finland.

I'm not saying these aren't good policies, but they aren't a fix for having more children.

You may need to update your priors, the countries where immigrants are coming from are dropping below replacement.

Migrant source regions are mostly going subreplacement as well.