I'm not sure you're entirely correct. A lot of people plan on downsizing their housing when they reach retirement age - Move somewhere smaller because you don't need to accommodate the kids any more, and further out of an urban center because you don't need to commute any more.
This is a net positive - It frees up more valuable real estate in urban centers for working-age citizens to utilize, and extracts capital from the property for retirement-age citizens to finance their retirement.
In this way, housing has been a stable and reliable investment for many for some time, and in a way that's beneficial to society as a whole. Quite different to what we're seeing here, an evolving dynamic which also threatens this model and puts people's retirement prospects in peril.