Conversely the last step to the door is as complicated as it is since till recently there was no plausible middle ground. You would always be sending out couriers so no real improvements in cost could be made.

But if you can get a drone or a robot most of the way there, that changes incentives.

I would personally love there to be a regulated, standard design for parcel drop off: but there isn't one. Not yet, and no human delivery will use anything I devise properly.

But if nonhuman delivery would, well now everyone looking at new motivation.