I would posit - admittedly without data - that outside of major metros where land is the clear dominant cost, most costs for housing increase is labor.
There are houses and empty lots available within 15min of downtown Cleveland that are selling for <50k. If you go up to $100k, there are dozens of houses. They’re all empty lots or houses that need renovations. If you want a new construction in the same neighborhood, it’s $300k. The cost difference is labor or materials.
Obviously Cleveland is a cherry-picked example but I used to live there so I picked my old neighborhood. San Francisco, Boston, Seattle, etc are obviously mostly driven by land costs due to demand and very high incomes.
All that said, some parts are gentrifying. Though mostly where developers can get large enough plots.
The point is that most of the cost of these homes are labor - even when land is nearly free (<50k in a city), you can’t get a “cheap” home that’s made to modern standards. If the land is free, there is no demand and high supply, but the house is expensive- it’s labor or materials driving the cost.
1) Materiels
2) Labour
3) Land
Perhaps housing is important enough to see the people do that. But even if you could somehow faithfully recreate the entire supply chain, the house won't be up to code. That 100-billion dollar company is going to spend all that money in the courts. Why bother?
Okay, sure, if the people can come together to recreate the supply chain they can also change the code. But then who actually wants to live in a 1960s home? Even the homes actually built in 1960 that are still standing, which is generally going to be those that were built to a higher standard, have been upgraded to modern standards, at significant cost, over the years because nobody actually wants to subject themselves to the 1960s.
And even if you could build the perfectly equivalent house with modern supplies and people actually wanted to live in them, there is still that pesky labour cost, which is a significant portion of the building cost. Yes, the median income of a full-time male in 1960 is almost exactly the same as the median income of a full-time male today, but the median income of the population at large doesn't tell the story of those building houses. Someone who would have worked on a job site in the 1960s is more likely to work in something like a restaurant today. As a result, of those who still are willing to build houses, you have to pay a lot more to get them to show up. "The trades are where the money is now" may have become somewhat of a meme, but there is also a kernel of truth to it.
Now, a business that can make modern houses less valuable will be on to something. That's a 100-billion dollar company. But also a hard problem to solve.
They also have better insulation and construction, they’re all wired for electricity and plumbing, they all have advanced HVAC. Fancier kitchens with more plumbing, appliances and nicer materials. People have access to more furniture and fixtures and appliances to fill more home - no one needed laundry rooms before a washer/drier was invented. Few had garages. Don’t let survivorship bias fool you - the 1950s homes that working class families had were not that nice.
The homes today cost more because more goes into them. We could all live in stuck huts we made ourself like in 1750 and everyone could afford two houses in 2024. Instead, housing has gone up because the utility of that housing has gone up.
Oh and of course we’re not making nearly as many per-capita as we used to. So the scarcity is going up.