Poor people might take "the robocab from hell", but just as I don't order "the humancab from hell" now, but order from the slightly more upscale "clean, air-conditioned high end sedan with blacked out windows and wifi" for just a slightly higher fee, people who earn more will still have alternatives, yet will still benefit from the cost reductions.

The difference being that poor people will have the "robocab from hell" alternative rather than have nothing they can afford, and that more people will afford said high end sedan when it's self-driving, and will be able to justify it more often, and more people will afford to trade up to even more luxurious services.

There is already a marked class difference in commuting in London: Low paid people take the bus four two hours+ for commutes that'd take less than half that if they could afford the train from the outer fare zones (bus-rides cost the same within the entire London fares area), so transport is already today segregated by income. A lot of the longer bus lines makes no apparent sense until you realise that low paid people often can't afford the train, or a car.

Uh, what? Cabs are already really popular. Why would a self driving car be "from hell"? You think they can't be cleaned?