I suspect that given peak loads, utilizations, etc. there are pretty unfounded assumptions about the economics associated with what would in effect be robo-taxis. Drivers today make, what, $10-15 per hour? So one would need to explain to me how taking that cost alone out of the equation suddenly makes using taxis and limos in place of private auto ownership an economically sensible thing for the majority of people in the majority of places where it isn't today.
The comparison is between a digital computer and an organic one (i.e. a human driver). Furthermore, one can't just assume that a car can drop a person off and head out to the suburbs to wait. That's a huge potential cost in both congestion and energy.
