Unincorporated but not unowned and there's a huge amount of infrastructure and money required to setup even a small town ex nihilo in some randomly selected part of the country.
Because beyond doing it by hand and setting up a city sized septic system the equipment for stuff like processing waste and preparing water is extremely expensive and the only sources want lots of money for them. It's doable just very delicate and requires permission and buy-in from actors in the existing system.
