They usually start as modest settlements of like-minded people, drawing in more members as they thrive and bleeding off members if/when politics and drama spoil the relationships among the people that live in them. Many collapse, others transform and sustain, and others eventually integrate back into a world that moves closer to them. Along the way, in their isolation and because of their strict rejection of prevailing norms, they naturally get kind of incestuous and weird in terms of ideology, practice, etc.

While you're free to try to start a new one on your own, if you're inspired to do so, you can also probably find some that are more or less practicing the kind of lifestyle you have mind. But it probably won't be an exact match for your dream, as no two people have quite the same vision of escape or prosperity, which is something that would apply to your hypothetical community as well.