True. To some extent, even a good mortgage rate trickles down to one's family. Some kid is going to inherit their parents paid-off house. The problem is that people have more than 1 kid, so most of them don't get that benefit and we keep building new homes, I guess.
Only 1 kid can inherit a house, sure, but out of two marriage partners it’s enough that only one inherits it. In this simple model, you only need to build new homes if you have more than two kids per woman, which developed societies are not on track of achieving.
Practically though we build new houses because old houses tend to not be in places we want them to be, and are not large and nice enough to our liking.
