I would expect anyone that wants to live in an earthship, would want the whole
permaculture package. Greywater, etc can be a great contributor to a healthy
yard. I would think even a community could have multiple earthship homes surrounded by a
perennial food forest, in a similar manner to the video
Geoff Lawton had about a community that's I think near 30 years old in the US.
And the community can beget neighboring similar communities.