Which very few people do, and even if they did, with a growing population, more single people, and more property speculators, demand still outstrips supply.
Downsizing also increases demand for lower end houses, pulling the bottom of the market up.
Yes we really want a bungalow so even in my seventies I am still perusing the property market. The trouble is that bungalows within easy walking distance of town are few and far between and usually have not been updated or maintained in the last twenty five years. Plus nobody builds them anymore.
Building bungalows would clear out the lone widow/widower or a couple from their big house which is difficult to heat or clean. There is obviously no profit in building them. However older is better, more garden and no stupid freehold charging or leaseholds rising by the year.
If I can get one, this house in prime catchment for primary and secondary schools will be back on the market