The answer to your question is basically "no". Humans aren't getting better at driving in the aggregate - new ones are born, learn to drive, get better, then ge

The answer to your question is basically "no". Humans aren't getting better at driving in the aggregate - new ones are born, learn to drive, get better, then get worse, then die off. On average humans are as good as they're going to get (with small variations due to culture and different training programs). On the other hand the self-driving cars are just getting started. It's entirely reasonable to suppose that they may surpass the average human in the next X years. And they won't get old and confused and eventually replaced with new cars that have to learn from scratch -- they should get more or less monotonically better. I think the optimism is warranted even if the timeline and technology is uncertain.