This isn't just about Uber -- all semi-autonomous cars are going to have this problem. The people behind the wheel will become distracted, increasingly so as the technology becomes better and they need to intervene less and less often. Even people who are trained to pay attention while testing self-driving cars become distracted, so we can assume the general public will become distracted too.

The only viable autonomous cars are ones that will never require human intervention, because humans aren't able to intervene effectively and may make situations worse as they snap out of a distracted state. But we can't get to full autonomy without first testing the technology, and no artificial test conditions could replicate the complexity of the real world. Society will either learn to accept some avoidable deaths during the testing phase or will ban the technology. I suspect a few more incidents will result in a ban, and we will not have fully autonomous cars for a very long time.