Sure, within a relatively homogeneous and sufficiently “socially isolated”* community the social cost is light.

(*: in the sense that “social minimum” pressures from outside don’t affect it significantly, including by making at least some members “defect to consumerism” and start a consumerist child-pampering positive feedback loop.)

I seem to think that such communities will not become very rich, but I can’t justify it other than with a vague “isolation is bad for growth” idea, so I don’t trust my thought.

Do you have any examples of “rich” societies (by current 1st-world standards) which are socially isolated in the way you describe? (Ie, free from “consumerist” pressure from inside and immune to it from outside.) I can’t think of any.