I'm only using 5 people with 3 cars as an example. In reality it's hundreds upon hundreds of people and proportionally fewer cars. I understand there are challenges with dealing with humans that will disappear when we switch to robots, but I can't see the API changing very much. The concept of a vehicle network, customers, app, doing clever things to anticipate traffic and customer desires on certain days, all of these things take (I would imagine) years to understand and optimize.

Your claim that operating such a network with humans versus robots, on a logistical (API) level, have "almost zero in common" is rather brash.