It;'s not pessimism, it's informed consideration
In common with all these confident predictions of the inevitability of autonomous vehicles, thinking it's just a question of safety fails to fully consider the ramifications and changes involved in the technology.
For example, you say that once the increased safety is established, the insurance companies will be "happy to insure them".
Insure **who** ?
At the moment, "car insurance" is actually "driver insurance". Some drivers are clearly safer than others. If you have an Advanced Drivers Test under your belt you can sometimes get a premium discount, and of course No Claims Discount also supposedly reflects a demonstrable "safety" record (actually, insurance liability record which isn't necessarily the same thing).
But in an autonomous vehicle with no driver at the controls, who exactly is the insurance company "happy to insure" ?
It cannot be you. As merely a passenger you are not a factor in any liability any more than your passengers are currently when you are driving under the cover of your insurance (unless it can be established that the passenger was actively interfering with your control of the vehicle).
Is it the specific installation of the car control and management software in your specific vehicle ? Good luck with that. Since that specific installation is identical to every other installation of that same control and management software you are looking at a ready-made class action pointing to the car manufacturer being liable (and/or the company that developed the software, if it wasn't the car manufacturer themselves).
But *is* the manufacturer of the car liable ? They only built the thing, they didn't sell it to you. That was the dealer, actively marketing and selling a machine where the control systems that determine it's danger to the public are an intrinsic part of the product. In contrast, currently, they can sell a car to any meatbag they like, but the law then determines who is legally permitted to operate that machine on the road, via driver licensing etc.
Or is it you, having chosen to purchase such a vehicle and abdicate control - does that very decision render you solely liable for the consequences of that decision ? Any lawyer worth their salt will easily have any such claim dismissed (you only allowed to abdicate control because it was established sufficiently that this was the "safer" decision and had you known that it was not you would not have agreed to abdicate that control - i.e. the responsibility falls back again on the technology or the industry).
The insurance companies would like to keep things pointing at the occupant of the vehicle, because if it falls back on the dealers or the manufacturers then at a stroke the entire market for driver insurance disappears and is subsumed into the public liability cover of those businesses.
I'm pretty sure the insurance companies would NOT be happy about that.
It is a much, MUCH more complex problem than simply establishing that driverless cars are "safer" than meatbag controlled cars. Those self same meatbags are what make identifying liability relatively simple and THAT is the real challenge of these things, not the technology.