localizing and streamlining production

These are two distinct goals, sometimes that work against each other. Localization is often a tradeoff between saving energy on transport and logistics versus economies of scale in production, and the right balance might look different for different things.

The carbon footprint of a banana shipped across the globe is still far less than that of the typical backyard chicken, because the act of raising a chicken at home is so inefficient (including with commercially purchased feed driven home in a passenger car) that it can't compete on energy/carbon footprint.

There are products where going local saves energy, but that's not by any means a universal correlation.