They'd need some digital infrastructure and open online marketplace, map or index, and use local shops as repositories for goods. For this to work they need some kind of automated delivery, like drones, or eTaxi/Uber passengers who take on delivery jobs.

Let's say you take an Uber from your friends house to your home, or you shedule your electronic car to "accept packages", and some shop owner drops you a package along the way that you deliver to a neighbor of yours.

You need a good system to make this work, so that shop owners (real world repository maintainers) and traffic participants are on the same map. Of couse would you take a a package if the friction is low enough, or you're stopped by a traffic light anyway and/or get some compensation for it.

Cars as investment (putting the car to work), instead of a constant cost factor for private ownership would be a game changer for private consumers. This might be possible soon with more automation in the infrastructure in place.

But they could do the equivalent of the amazon market place given their expertise in logistics.

They just need to do fulfillment as a service. It would be a huge business.