No cities on the Moon: a billion tons of water is not enough for sustainability
(www.frontiersin.org)
The ongoing automation is the evidence. The trend is to fully automate the whole production chain and that will lead to decentralisation, because centralisation only makes sense with human labour.
Human egoism isn't bad in itself. The problem is that it conflicts with altruism. That's where it gets destructive. But this can be solved. If everyone can automatically produce what they need themselves, there's no more competing for who's going to be the one providing and the one taking. The roles merge. Egoism and altruism become the same thing and neither stays destructive.