Its the banks. People still build their own houses, but they aren't "worth" much if you do, compared to if a construction company did it. The reason is the system of "comps" - estimated values based on similar houses. But banks won't buy houses that they can't assess, and "comps" don't work if people are building whatever they want. When you get a mortgage, the bank buys the property and you just pretend to be the owner - no comps, no mortgage. So there's actually broadly 2 different housing markets - the market for mortgagable homes and the market for everything else. Because financing is easier with banks, the market where homes were built by a company goes up in price faster, but also there's less competition on the supply side. You would think it would wash out in the long run, but again, the banks are there fucking it up. The construction companies don't build with saved cash. They build with borrowed cash. Borrowed from whom? Lol. The same banks that buy them. See the racket? And they do their own homework on the housing market - they lend less to companies if they think demand is too low. They lend on both sides, to the homeowner and the builder, and they control the spigot of available funds on both sides.

Starting to see why I hate banks? Its not as simple as time value of money. All usury must end.