Its no secret that Uber's plans for the future involve replacing drivers (the thing that takes most of the cost of a taxi today) with self-driving cars, so the cost of using an Uber becomes cheaper than the cost of owning a car.

Its a bit like Netflix; the bueinss started out as a DVD rental, but the plan was always to be an online streaming service.

It puts an interesting spin on the idea of market disruption; taxi services are being disrupted by Uber today, even though they are effectively the same kind of business. But Uber's advantage — building a business ready for a transition that is still on the horizon — hasn't even come into play yet.