Where I come from, you do not become a millionaire by working an average job. If you don't happen to be at a C level position, you will never become millionaire level rich by working for other people. If you have a middle class income, it means you have no more than middle class maneuverability. It isn't enough to become a multi millionaire under your own power. You have to start your own company or repeatedly make very good investments to really move up.
Owning something that suddenly has an inflated value does not necessarily make you rich.
Let's say you own a car. You need that car (maybe to take care of a relative). You can afford your car with your middle class income. Over night it gets replaced by a golden car worth 1 million dollars. If it's the only golden car, you are rich. You can sell the golden car and replace it with a reasonably priced one and still have about a million dollars.
But it's different if in the same night all cars become golden cars, including every car leaving the factory. Even 20 year old cars in dire need of repair have become golden one million dollar affairs. Now you're not rich. You can only exchange your golden car for another golden car.
If you sell your car and use the money for anything else, you will never in your entire life own a car again, because your income just can't provide for it.
That's how people stay middle class with a middle class income even though the house they live in suddenly is worth a million. It's about maneuverability.
> Unaffordable housing comes from inadequate supply, which comes from older generations not permitting enough housing to be built in the high-demand areas.
Unaffordable housing has to do with demand and supply, yes. What many people overlook is that not all demand stems from people wanting to live somewhere.
Land ownership has become an attractive way to park money the last 15 years. And there is a lot of money that needs parking. The last burst of a housing bubble caused one of the biggest ways to park money - lending to other people - to shrink dramatically (mixing subprime loans as a marketable bundle turned out to be a bad idea). Interest rates went down, making it even less attractive. The money now gets put into an equally inflated stock market, some of it into Silicon Valley style venture capital bets, and another huge chunk into real estate. So there are a lot of very rich and influential people who would lose a lot of money if those house prices would start to fall.
And even if you would meet the demand of those people who just want a place to live, you will not satisfy the demand for investments.