> ... The workers will have worse and worse living conditions until they're reduced to effective serfdom.
Both outcomes are possible; it basically depends om whether the high productivity of the most expensive cities is truly exceptional - in which case it won't benefit most workers - or something that can be readily replicated in the rest of the country. We've mostly seen examples of the former in places like the Bay Area: there's only a limited number of Big Tech unicorns around at any given time, after all. But the latter is a theoretical possibility, perhaps driven by more ubiquitous sorts of sustained technological change and innovation.
Both outcomes are possible; it basically depends om whether the high productivity of the most expensive cities is truly exceptional - in which case it won't benefit most workers - or something that can be readily replicated in the rest of the country. We've mostly seen examples of the former in places like the Bay Area: there's only a limited number of Big Tech unicorns around at any given time, after all. But the latter is a theoretical possibility, perhaps driven by more ubiquitous sorts of sustained technological change and innovation.