I guess all of this just means I will continue to not buy anything approaching a new car.
I don't want any bit of the car having any connectivity to anything. I want my intent as the driver to be transmitted from my hands mechanically to the important parts of the car without any opportunity for a malfunction (intentional or otherwise) to compromise it.
I thought about all of this when the "sudden acceleration" hoopla over the Audi 5000s in the 80s, and then Toyota Priuses much more recently, was in the news. I remember one such Prius story describing how one of the supposed victims tried to turn off the ignition, but the car was equipped with one of those pushbuttons instead of the good old key in lock cylinder ignition switch that has been in every car I've ever owned. Naturally, when speeding down the highway, the car declined the request to have the engine turned off, and the person who was frantically giving this story to the police on the cell phone supposedly didn't survive the car's refusal to obey. Having never operated a car with such a "feature," I have to wonder if it has the same "hold it down if you _really_ mean it and it will turn off eventually" feature that modern computers, phones, tablets, etc., have.
With my car, if I want a certain action performed, it happens unambiguously and without some computer pondering whether it really wants to do that first. If I turn the key off, the power to the ignition and fuel pump is cut off-- no ifs, ands, or buts. If I depress the clutch pedal, the engine is disconnected from the transmission, without question. If I turn the steering wheel, the front wheels change their angle. I may have to muscle it if the hydraulic assist is not functioning (the primary reason being that the engine's not turning), but there's no computerized anything that would ever even present the possibility of trying to thwart my intent or doing anything without my say so.
While my engine is run by a computerized control, it would require the removal of a body panel and removing a service cover on the ECU to get to it. There's no other interface. There's no wireless... anything. There's no flashable firmware. There's no "entertainment" system... there's a car stereo that isn't tied in with anything else, but that's it. No bluetooth, no wifi, no cellular connection. It's a car; its purpose is to covert chemical potential energy into kinetic energy in a fashion controlled by the driver, and it seems to do that pretty well even without all of this modern "improvement." None of the computerized systems in the car were ever questioned for their "security."
"Security" concerns for cars like mine were and are all about physical things, like using a slim jim to open the car door or whether a slide hammer could expose enough of the ignition innards to be able to hotwire the car. Of course, those things are still a concern; thieves can steal them, no question, but unpatched zero-days are not among the concerns.
If I were to go buy a new car, how would I even begin to understand the insane amount of crap that carmakers hang off the relatively conventional car body these days? I'd want to understand it so I can block it, stop it, shut it down if I can. Those things are not all that hard to do, but you have to first understand what's happening, and where in the car the offending things are happening. I don't want a rolling computer! I know too much about how vulnerable they are without constant attention and work to mitigate it, and I know too well how quick hardware manufacturers love planned obsolescence. It was already there in cars, certainly, but it had to do with mundane and understandable things like parts that wore out, not security vulnerabilities that need to be patched, but aren't.
I don't even want to be in the place of needing patches; I want my car to behave as it always has. One other poster has written about software "upgrades" reducing the artificially-limited maximum speed of the vehicle. Not acceptable! If the way my car operates is going to change even the slightest bit, it should be because I've changed something, swapped a part or a whole series of parts somewhere. That's how automotive stuff has been in every car I've ever owned, and I am not about to change my mind about it now. Certainly, I do not want any software update being pushed into my car without me first reviewing and approving each of the changes... if I won't tolerate that with that unusable piece of crap called Windows 10, I am not going to tolerate it when we're talking about a mechanical device that can kill me if it messes up.