Comment by tzs

> Ten years ago, commingling was a necessary optimization. If seller A (county A) and seller B (county B) both sold the same widget, Amazon treated them as a single distributed liquidity pool to guarantee 2-day prime shipping nationwide without forcing every small seller to split their stock across 10 warehouses.

I don't see why that required commingling. When I click on a Foo in my Amazon search results show me the Foo from whichever of A or B is close enough to meet the 2-day shipping guarantee. If I care which of A or B it actually comes from I can click the option to see other sellers and decide if giving up 2-day shipping is worth getting my preferred seller.