Cost versus scarcity marks the difference between what abundance can fix and what it cannot. AI and robotics may drive down the cost of food, construction, transport, manufacturing, diagnosis, education, administration, energy, much care, and routine legal work — which weakens the oldest objection to a standing floor, we cannot afford to carry everyone, and makes capacity circulation the live question. That is the cost problem, and it is largely solvable.
Scarcity is different. Some things stay finite in even a very wealthy society — land in desirable places, transplantable organs, specialist attention, human companionship, quiet, wilderness, some treatments, unique cultural objects, political attention, time, physical space, positions of authority, ecological carrying capacity. No amount of production makes those infinite. So the framework cannot rest on abundance:
AI may make standing affordable long before it makes every desired resource abundant. The framework cannot be a post-scarcity philosophy; it has to work under scarcity too.
That is why standing needs a separate allocation theory: affordability answers can we carry everyone? while scarcity keeps asking who gets the scarce thing? — and the second question never goes away.