California Forever is a debacle only because it can’t be built. It would do fine. It can’t be built because its proponents adopted a foolish, deceptive, forgiveness-not-permission approach to siting and acquiring land for the project.
It depends on the region. The demand in and around the SFBA is so intense, and the work requirements so varied, that you can get prosperous neighborhoods of even the shittiest design way out towards Dublin + Livermore. De novo districts at a distance can be debacles, or can be successes. It depends.