A nicely thoughtful perspective. You are quite correct that "buy local" is not a simple equation, certainly not a bromide. You dissect the issue well. I couldn't agree more with you that paying workers good wages is the key.

I am not entirely convinced that linking "buy local" with mercantilism is correct, though. Mercantilism is what we today call "protectionism," i.e.--ensuring monopolies on production that benefit the wealthy land and business owners. To me, that's the salient issue today: does a policy or practice benefit a few or the many? In terms of food production, the irony is that the giant agricorps benefit the few shareholders while a food economy based on small-scale farmers benefit more people.

I'd be curious about your learned assessment of my arguments in this piece on food production, https://medium.com/discourse/sorry-veganism-wont-save-the-planet-1f2b3ff6e51f. I use the "buy local" idea in terms of carbon footprint rather than local economic prosperity.