I would love if we could reduce the vehicle fleet in urban areas by 90%, whether it is AV that get us there or something else. It would be a shame if this 'revolution' ended up increasing the VMT for many people though, as that would be a step backwards. I think there's plenty of room in this market for either competing private AV fleets, or even a substantial public fleet.
Here, check this out: AutoVots transport single passengers; TaxiBots share rides among multiple passengers and allow for slight detours. There will definitely be an increase in the total amount of vehicle miles travelled over all vehicles. More trips with more people over longer distances are nearly inevitable. Whether the amount of miles per trip will increase or decrease is up for debate, though.