Let's try looking at birthrates another way: Japan might be one of the few rational countries in the world. If the economy is not growing in a way that support

Let's try looking at birthrates another way: Japan might be one of the few rational countries in the world. If the economy is not growing in a way that supports having 3-5 kids per family, with a high quality of life (very important detail)... ...then perhaps the rational response is for birthrates to drop so the population can reach a natural size where quality of life is acceptable for the kids that are born. Countries that continue to grow their population over everything else wind up being pretty miserable places to live over time.