Re: Not a problem solved
"but the fact is that people are lazy and will always try to save costs where ever possible."
I think the ownership model changes when self driving vehicles become commonplace. Why would you need to own one? I know there are some specific use cases where having access to a specific vehicle is important - my son for example is a wheelchair user and has lots of kit to carry around with him and it's far easier to just leave most of that kit in the car.
In the main though, why own something that gets used for a tiny portion of the day? I trhink a lot of the legla questions about using these things get solved in a lease model too - even if you lease something to be permanently available to you, having it owned and maintained by the manufacturer gets rid of all the problems you list.
As for duff kit and dirty sensors - I'd pretty much expect these vehicles to refuse to depart if they don't have a defined minimum set of kit available, and I'd expect them to take themselves off to be fixed or call for service when things do go awry.