zinssmeister is viewing the /approximate/ duration of a commute as a 'sunk cost' (in time) for the worker. If the jobs are all centrally located even insane real-estate and urban development practices that drive the workers out to suburbs can make economic sense once the workers are conditioned to put up with that abuse.
They are saying that many, in fact most, 'local' jobs exist with relatively little opportunity cost for change.
Contrast this with a hypothetical future of (E.G) New York, where in 30-50 years they've gone full caves of steel: banishing cars to the edge and having a multi-layer dense mesh of rapid electric motor powered transit and living which intermingles living, working, recreational and (deep underground) industrial productivity. There the opportunity costs might also be the same, but the cost (in time) of migrating might be less, and favor walking on moving belts for a combination of speed and exercise.
They are saying that many, in fact most, 'local' jobs exist with relatively little opportunity cost for change.
Contrast this with a hypothetical future of (E.G) New York, where in 30-50 years they've gone full caves of steel: banishing cars to the edge and having a multi-layer dense mesh of rapid electric motor powered transit and living which intermingles living, working, recreational and (deep underground) industrial productivity. There the opportunity costs might also be the same, but the cost (in time) of migrating might be less, and favor walking on moving belts for a combination of speed and exercise.