What if I only want to live someplace for a couple years? Building a house that I want to live in for the next 40 years makes sense, but if you have no reason to think life will keep you in the one place for 40 years renting may be a better deal - let someone else take the risk of building a house and hoping someone comes to live in to.
It's called cooperative. If I'd like to live in apartment complex, I'd post an ad like "Buy an apartment in a future complex for a low price of X! Move in in only 2 years!". (Cost to build Y, number of apartments Z, X = Y/Z).
And it's not something new. When price is lower than market, people do buy it.
You’ll need a construction cooperative. IDK if those can compete with large construction companies due to the economy of scale. The construction cooperatives were a staple of late Soviet and post-Soviet Russia, but were essentially outlawed later to make way for large construction business and mortgages-backed construction.
I'm not against them, but they are not the right answer for everyone. They are great if you want to live in the same apartment for a few decades, but if you move they become tricky.
To live in it.