Earlier quoted context omitted.
I think there's a more concrete measure of value: house prices related to income. Historically (Robert Shiller has a chart for the US going back to 1890) house prices (and mortgages and rents) have maintained a stable relationship with income. Occasionally that relationship is strained but it has usually fallen back in line. One exception to this was the extraordinary, ongoing, support to the financial system post-20…
There’s no rule that you should be able to afford a house on a middle class income. In fact in many countries, particularly in Western Europe, it’s unimaginable that you would be able to afford a detached, single family home on a middle class income. Lots of people in that situation will live in apartments, row houses, or condos for the rest of their lives.
This isn't really an ownership issue, it is an occupancy issue. Monthly rent needs to cover the expenses of a property including any mortgage, property taxes, etc as well as maintenance, so rents wind up tracking house prices. If you can't house the middle class, a) they're not really middle class and b) you have a societal problem.