Not to undermine what you do, or what any doctor does, I honestly believe driving a car to be something that's tougher than surgery (for a robot). Now of course, when I say 20 years, I think by then we'll have robots who can do a number of 'routine' surgeries at least. Maybe each robot is specialized and can only do 1 surgery but there's 15 different types of robots who all have mastered 1 surgery.
When performing a surgery, I'm sure you need to think on your feet a bit, but how many scenarios can you think of that might happen in a surgery ? Knick a blood vessel, throw a blood clot, drop a tool in the patient, unforseen bleeder/hemorrhage, alergy to drug, etc... I'm sure there's quite a list...
How many scenarios can happen in a driving situation - magnitudes more than a surgery, because a surgery is in an isolated room and controlled environment. Driving is not. On the road you need to worry about:
* Pedestrians from front, and sides.
* Animals from all angles.
* Rain/Snow. Hydroplaning.
* Traffic construction.
* Other idiots on the road.
* Helicopter Crash.
* Police Chase.
* Sheep stuck in the road.
* Forest fires. (Obey the speed limit or floor it to escape?)
* Billing (If you're an uber ai car).
* Drivers that are angry, sad, happy, distracted, having a medical emergency, falling asleep.
* Natural disasters like an earthquake.
* Bad directions.
* Loss of internet/connectivity.
* Running out of gas/electric.
* Curves in the road.
* Signs that could be permanent or temporary.
* Obeying traffic laws.
* Being aggressive when needed to take a lane.
* Be courteous and move over for faster traffic passing on the left.
* Sensor failures and malfunctions.
* Tire blowout.
My point is it's a LOT more than just forward/back/left/right, if you had an enclosed building w/ a driving track, and could control who was in the room, where they were standing, what their jobs were, before the car took off, then you mitigate MANY of the issues that self-driving cars have, and the technology as it exists today is good enough for that scenario.
Personally though I see us (hopefully) moving towards a post-scarcity society, sort of like Wall-e, but hopefully without the laziness (I'm sure we can find fulfillment in other ways) -- Research for instance will be a hobby instead of career because people --especially scientists will always have curiosity pushing them forward.
If we survive global warming, the next 100 years is going to be unfathomably different from the last 100...