Low Birth Rate Is and Isn't a Problem

The fertile will reign supreme.

In most wealthy countries, populations are declining, with couples having fewer than the 2.1 children required to maintain the population. This is a problem for myriad reasons, including many nations' unsustainable pension / social security policies. My primary concern is that fewer people means fewer brains, and fewer brains means slower progress.

However, all is not lost: plenty of countries have growing populations. Most of the people in them want to live in developed countries. Even better, for multiple generations, the migrant families continue to have many children.

I'm brushing over the self-harmful reluctance to accept immigrants in developed counties. But let's assume they realise how much economic growth they're leaving on the table with their cruel and nonsensical immigration policy. Even if only 10% of couples have three children, those families with the culture and genetic predisposition to have more children will become a higher proportion of the nation. Eventually, descendants of pronatalists will outstrip the reluctant parents. Populations will not only stabilise but grow again.