[michaelmrose]

Driving in a circle still isn't free it either costs gas or electricity. When you park your car you are constrained to park it relatively nearby. Logically your car lacking a parking spot at your location will seek one nearby until it has traveled far enough that it is logical for it to turn around and drive back to you.

In some cases perhaps it will rejoin the pool of available cars and you will picked up by a different car.

Perhaps retailers will be yet more likely to offer to ship selected large or awkward items directly to your home after you have picked them out.

[jessaustin]

Perhaps retailers...

Yes they'll be happy to pay a premium for delivery trucks that require no drivers. Time-of-day flexibility will enable serving more customers with the same size fleet. Many customers will be more willing to use delivery when they can plan around working hours and don't have to worry about tipping. Service levels won't be subject to mistakes in shift planning.