I.e. where does the drone land? How does the recipient pick up their package? What if you live in an apartment, how do you get your pie?
This make me think drone delivery is probably waaay more valuable in suburbia than a city setting. Delivery in the suburbia seems costlier currently (larger distances, lower densities so less stops per route, etc) and drones are well suited to deliver to a nice big front/back yard.
In cities - I don't see how they'll deliver pizzas, but maybe non-perishables can be deposited into receptacles on rooftops or street corners and picked up asynchronously.