Frankly if the only way you can make widgets is to pay your widget-makers just enough so that they don't die, or perhaps less, then in my opinion society should reconsider how valuable it considers widgets to be, or at least whether someone else can make widgets more efficiently.
Aren't externalities costs/benefits that accrue to third parties? But this doesn't seem to be in that category.
Obviously, when adults are trying to support themselves with this kind of job, we have a problem.
My point was that not every job needs to pay a living wage.
If you mean "a basic income, offered by the same organization in multiple places, should be adjusted for cost of living", I disagree. Moving some "extra" funds towards lower cost-of-living areas winds up being a feature - resources are shifted (slightly) away from concentrations of wealth and toward concentrations of people, where those disagree.