That works if people's only businesses are what is needed by the small community/tribe. We've reached a point where thanks to a millenia of technological advance, a fraction of the populace works in agriculture. Instead I work in a business that sells a niche enough product that we might have a customer ever other week from somewhere in Europe. In order for that to work, we can't only have customers in our town or its immediate neighbours.

So we can have more devolvement, an endless argument here in the UK, but centralised money structures, standards bodies, transport networks, etc are required for this to be feasible. Already we complain that the more niche ideas can be more successful in the US because there's a larger home market.