Total non-worker consumption is equal to the unconsumed portion of total worker production, the worker-to-retiree ratio is getting worse each year, and total productivity gains are stalling. Working-age adults have to get squeezed somehow on pain of retirees voting different policies, and housing/rent/mortgage is the least flexible in terms of household budget and least politically obvious pathway for it.
Next to that, the maximum price is largely defined by how much people can and are willing to borrow with a typical income for the location and the type of building.
And with location being in short supply, locations (and houses) go for maximum price. With rent going up, maximum price will come down, to keep total price the same.
This is the main factor, and it's a result of the monetary policy of the last decades.
Since this number has been increasing compared to wages, it's becoming less sensible to build apartments for rental. But at the same time, those are needed to increase density and availability of affordable housing in attractive cities.
It's a mess.
To get low house prices we would have to destroy Fintech of house loans which will not happen.
It is staggering. California in 1990 was 29 million. In 2020, it's 39 million. If this is not staggering, I don't know what is.