It’s easy to have a utopia when you live in a village where everybody knows each other. You don’t have to look to indigenous peoples for that. There are plenty of villages around the world where communities still thrive.
How do you achieve that in cities of a million people or countries of a hundred million? No one has figured that out yet because all the mechanisms we’re born with for building trusting, reciprocal relationships do not scale much more than a couple hundred people at most.