I’ve never spoken one-on-one with Sergey Brin or Elon Musk so I don’t know what they really think about autonomous vehicles. I can only give you my opinion.
My experience has been that people with technical knowledge and understanding think that autonomous vehicles are being tremendously overhyped and are something for the distant future if ever while non-technical people think they’re just around the corner or even already here. That leads me to conclude that Mssrs. Brin and Musk know that and don’t really care whether people are killed by prematurely autonomous vehicles. They just want to get in on the gold rush.
I repeat my proposal: strict liability. People who are injured by prematurely autonomous vehicles or the families of those killed by them should be able to recover from their developers regardless of intent or the ability to prove specific responsibility. All that should matter is the injury. Injured by an autonomous vehicle? You should be able to recover from Google (or Tesla or Uber).