I think that to trully give urgent delivery services a purpose we need:
- Abandon 0-day delivery services unless they serve a significant purpose, e.g. for immobile persons, delivering medicine, etc. That would erase like 95% of required labor;
- Reclassify the rest as a communal service, mostly on a regular schedule between known clientelle;
- Optimize paths between vendors (or hubs) and delivery targets for the remaining fleet. At this point a minimal system is upheld by a minimum number of members of community who don't need to hurry and use motor vehicles;
- Create an option to offload some delivery task to other community members who live nearby and go this route anyway, probably via some app;
- Allow for less urgent delivery jobs being posted, but always served by the members of the same community. Community collectively defines what non-critical deliveries hold value, e.g. delivering flowers for a birthday celebration can be seen as okayish to do.
Fetch quests, when optimized, provide some persons with meaningful labor that keeps up their physique, and their, and then others' involvement ties the community together and makes personal connections between people in it. Drones navigating the sidewalks humans use are irrelevant if the amount of labor needed is not overwhelming to begin with, and doesn't need to be optimized by producing expensive robots and computer vision models.