You're under the assumption you'll still be able to afford insurance for a non-autonomous vehicle, something I find unlikely if self driving cars are as safe as they've already proven to be in the million+ miles they've driven.
Use of self driving cars hockeysticks-># of human drivers plummets->premiums skyrocket for remaining human drivers.
You do realise that 1 million miles is an infinitesimal sample size, right? According to the US DOT, in the past 12 months vehicles have traveled just over 3 trillion miles on US roads[0]. It's also worth mentioning that substantially all of those autonomous miles were on freeways, which also happen to be the safest roads for human drivers. It's simply not possible to draw any meaningful conclusion from such a data point.
We don't have to quibble on data points; autonomous vehicles will continue to get better, at a faster rate than humans can get better at driving (or actually, you know, concentrate on it instead of eating, using their cellphone, texting, and so on).
Humans aren't obsolete yet, but we're well on our way.
Right now, in a lot of states, you can just post a bond in place of having insurance.
It also might work out that self driving vehicles end up reducing the rates for human drivers. I think a lot of road risk actually comes from a small pool of drivers, who will tend to be the most eager to stop insuring themselves. So even if if the pool of human drivers shrinks a lot, the risk involved could lead to lower rates than we see today.
Use of self driving cars hockeysticks-># of human drivers plummets->premiums skyrocket for remaining human drivers.