Much of the talk about collapsing birth rates assumes that every generation must be replaced. Don’t believe it. A falling birth rate is not, by itself, a crisis. The real crisis is in figuring out why your children aren’t having their own children.
The only people genuinely worried about low birth rates are the farmers of men who want GDP always to go up. After all, they can’t make much money on only a handful of peasants. Rather, a low birth rate is simply a sign that an ecological limit has been reached.