The birthrate in most of the third world is also declining, fwiw, and most of these countries are becoming richer. Immigration is a good solution if you have a

The birthrate in most of the third world is also declining, fwiw, and most of these countries are becoming richer. Immigration is a good solution if you have a low-context, high-income country, that poor or chaotic neighbors want to live in, but that's not a given and won't work everywhere forever