John Michael Greer puts together the historical argument for sustainable local economies.
In particular, the role of guilds (regulated the talent stream to maintain somewhat of a free market):
Thus in a restricted market where specialization is limited, a free market in which prices are set by supply and demand, and there are no barriers to entry, can make it impossible for many useful specialties to be economically viable at all. This is the problem that the guild system evolved to counter. By restricting the number of people who could enter any given trade, the guilds made sure that the income earned by master craftsmen was high enough to allow them to produce specialty products that were not needed in large enough quantities to provide a full time income. Since most of the money earned by a master craftsman was spent in the town and surrounding region – our blacksmith and his family would have needed bread from the baker, groceries from the grocer, meat from the butcher, and so on – the higher prices evened out; since nearly everyone in town was charging guild prices and earning guild incomes, no one was unfairly penalized.
(H/T Dale Asberry.)