What percentage of crashes can be attributed to that? Let's make it simpler, how many crashes per year as a raw number happen due to those reasons you listed?
Because out of all things I would be worried about when it comes to car safety, this is the one that is least concerning to me. Especially since for most modern cars that have such a thing as "software updates" in the first place, they have the driving subsystem and infotainment subsystem entirely detached (yes, even on Teslas). Very easy to confirm yourself by force rebooting the infotainment center and seeing that the car still drives just fine.
In summary, the infotainment system and the drivetrain definitely speak to each other and unless a secure architecture comes along, I would not discount the possibility of unintended interactions due to bugs. In fact, most famous car hacks start from the infotainment system and make their way into the drivetrain.
2. I don't have those numbers, in fact point of my post I'd that I don't know how we get those numbers. When I'm a passenger I'm terrified how distracted people can be by poor UI. I wish we had more hard data. Some studies are slowly emerging.
A good 10-20 year old car may have as good crash rating as many modern cars. top or average modern cars may be better than top or average 10 year old cars. Stats are interesting thing. But then there's the average driver assistance vs average UI vs average visibility vs average handling of these cars.
Bottom line, I don't feel less safe but I do feel differently safe, in my old Subaru and new Honda.