The zoning laws didn’t change in between. Japan got burned on property speculation, and no one no longer sees residential real estate as much of an investment. Also, no one wants to buy second hand structures, so your appreciation is limited to land and the existing housing on that land is a liability (buyers have to tear it down before building a new house on the land). Japan has a large amount of housing starts because they have a large amount of demolitions. Liberal zoning allows for this, for sure, but I’m not sure many Americans would be willing to go that route.