Not all countries are at 2.24 -- USA is at 1.62, so whether correlation or causation, many developed countries are nowhere near the replacement rate.
https://en.m.wikipedia.org/wiki/List_of_countries_by_total_f...
https://en.m.wikipedia.org/wiki/List_of_countries_by_total_f...
And Afghanistan is at 4.66
> developed countries are nowhere near the replacement rate
Doesn't matter because of the immigration. Population of developed countries is growing.