I feel like all these self-driving companies aren't actually in it to achieve the success. They know it's a long way off, they're just trying to hit enough milestones to get scooped up by somebody bigger. Perhaps with the exception of Tesla, who I have no explanation for. Self-driving cars are so far down the totem-pole in my opinion--if we're going to have to rework our roadways in order to accommodate self-driving cars, why not just innovate there?
A roadway can be MUCH smarter than a car. Each segment of smart road is unique, and only has to worry about itself and whatever cars are present in the area. Smart roads could be managed by a few operators (in fact one operator could shepherd many road segments).
Each smart car has to be able to account for all possible kinds of roads. Smart cars each require an operator who is essentially just sitting there waiting for the car to fail (and therefore the failures become more catastrophic as the tech gets better, since trust rises and attention spans fail).
Put the tech into the ROADS, and just let the cars listen.