Economists forget that people as well as buildings depreciate at a roughly predictable rate. Child-rearing is at least as essential as build- ing roads. Imagine if these four economies had invested less in infrastructure and more in people. They would not be facing a situation in which their workforces-unless replaced by immigrants-will decline dramatically within 20 years as the population over 65 continues to grow. The payback for years of what may well have been the misallocation of resources is not far in the future.