1) The physics of driving isn't random, so it could be said that there are no accidents in autonomous driving, only oversights.
2) It would set a minimum performance level by making it prohibitively expensive to have a dangerous car. Those who test responsibly would have a low enough injury rate that they could deal with the risk by taking out suitable insurance.
3) It would provide a strong incentive to make the best car possible and not to take expedient shortcuts.
4) Over time automatically liability would become irrelevant if it asymptotically forces the injury rate to zero.
5) We have an historic opportunity to create a culture that will eliminate the danger of cars. It might have an increased short-term once off cost, but a huge long term payoff in the reduction of health costs and human misery. If we miss this opportunity we will be stuck with the long term cost of an industry that will be competitively driven towards poorer performance, potentially against the will of the majority of players, by the actions of a few.