Personally, if Apple creates a standard car simply with a great software experience (I'd expect at least a few small novelties), and not too expensive, then I am totally in.
a) You can operate it without talking to it
b) It has dedicated knobs/levers/switches for primary essential controls.
c) It doesn't require internet connectivity, continual tracking/telemetry etc.
I do assume it'll be a locked-down, walled-garden experience, only serviceable at Apple Stores (which will open garages at some locations), assuming they can get away with that legally. They'll reject any non-Apple-genuine part, of course.
But to your point about voice control, I do expect Apple will try to make that really good. Touchscreens suck for keeping your attention on the road when you want to change the heat temperature or change songs or stations. Physical controls are better. But good, painless, non-frustrating voice control is by far the best option for avoiding distractions and keeping your eyes on the road.
Apple knows how to build interfaces. Including interfaces outside of software. I suspect it'll be the primary thing they focus on in the product launch video, how they didn't screw up the UI and there will be knurled titanium wiper speed ring switchy things and tactile feedback in the damn mushroom leather wrapped heated steering wheel and Jony Ive whispering directions, seemingly inside of your head.
I don't want Apple forcing their excellent design sense down my throat, I'd much rather have decent design I don't have to use.
Just one tiny example: see the manual dial or “crown” on Watch, AirPods Max, and now Vision Pro. You could easily imagine those products without an unnecessary manual “dial” when there is both voice (Siri) and software controls. But, you still have a “dedicated knob”.
Not sure which iteration of it you have, but I've actually found the software on my 2022 E-Class to be surprisingly decent. I generally prefer plugging in my phone and using Android Auto, but if I don't need Google Maps to get where I'm going, I usually don't bother with it and the car's own system is fine.
You ever heard about Autosar as a software middleware that is in use for years by most of the OEM to decouple software and hardware development?