We are not talking about economic theory. We are talking about house prices. Time after time it has been seen that free-enough market can lower the prices to affordable levels.

We don't need economic theory for that it's just common sense. Humanity has been erecting structures to live in for approximately our entire existence. The modern economy is mechanized. How could a wood frame structure or a small high rise possibly be unaffordable if the market is functional?

Stop and think for a second. Someone in good health with a willingness to DIY and a sufficiently flexible schedule can literally build their own house from the ground up. It's a substantial time investment but not actually as much as you might think. Housing isn't very resource intensive compared to the rest of the modern economy.

The only possibilities I can imagine to explain unaffordable housing are broken regulations, critical levels of resource exhaustion, natural or man made disaster, and gross economic dysfunction.

Of course demand is elastic.

Do you think, people will migrate to a city with an unaffordable housing (unaffordable for them)?

Unless you are living in North Korea, the competition is also there.

The regulation is single family zoning. Zoning makes it impossible to stack high rise apartment buildings in the areas that people want to live in.

The invisible hand is zoning. There's plenty of investment available but you literally aren't allowed to build what would be useful in most cases.

Sure you're free to go out into the middle of nowhere and build all sorts of wild stuff but there's no market for that because that isn't actually what anyone wants. You can't blame the investors when what people actually want to pay for has effectively been outlawed.

Why the investment funds have to build the houses? Houses has been built/funded from zero by the future owners since forever, either individually or through cooperatives. That way, "investors" don't need a positive ROI, and they happily lose money overall if they get a home.

I know some people that are currently "willing to invest" in buying a ship container or two and transform it into a house to get costs down. The problem? Regulations don't allow them to put the container in their own property.

Which isn’t quite accurate as for example people prefer to move out of their parent’s homes while young adults but aren’t necessarily homeless if they don’t.

Basic housing is a necessity, but people also huge homes and 2nd homes etc. So housing policy should therefore be more complicated than simply subsidizing anything you can call housing. Capping the home mortgage tax deduction at ~median home prices for example is probably a better use of government funds.

That is the object of the sentence. He is asking who the subject is, in other words the thing or person that is doing the housing of the people. Is it the government? Is it you? I'm currently responsible for housing myself, which is annoying so I would prefer someone else take on this responsibility.