It seems like drones will mainly be delivering stuff that's locally available anyway, since otherwise it will be at least an overnight lead time and so the pack

It seems like drones will mainly be delivering stuff that's locally available anyway, since otherwise it will be at least an overnight lead time and so the package might as well be delivered via truck that's cheaper to operate. If you have to go to a convenient centralized location to pick up a locally available item, you might as well just go to the store and buy the item without involving a drone. Maybe if you have drones with a large enough service radius, you can centralize warehouses enough to have a much better selection than convenience stores. If you're still delivering to centralized lockers, though, it seems like packages could be batched in trucks as they currently are. I suspect sparsely filled trucks would still be cheaper to operate than drones, even with similar delivery times. The value of drone based delivery really seems to me to be in getting packages exactly where they are needed faster and cheaper than sending it via direct courier.