Except when they're not. I made the mistake of assuming the + and - buttons on the steering wheel of my Subaru had the same functionality as those on my Prius' steering wheel, which incrementally adjusts cruise control speed.

On the Subaru, they are clutch controls. The result was downshifting into 1st gear going 70mph/100kmh+.

You can probably walk up to a Gnome, KDE, Windows, Mac or Chrome computer and use it after a couple seconds. I don't fully understand all the configuration options my car has - I set it to "comfort" and that's it and yet I can drive it.

I don't think I can tell you immediately whether my laptop is running under Wayland or X (I only can because Wayland and FontForge haven't been talking for some time). Does it annoy me? Yes. Does it annoy me to the point of anger? I'm an adult. I have other things going on in my life besides graphical back-ends.

You can. I can. With a small adjustment period where the hotkeys or actions you expect to work don't and minimal annoyance and you make small adjustments to do the same task.

This is not how average people are AT ALL. Let someone use one of the above and give them something new and watch them be frustrated for at least the first entire day of usage with continuing friction happening for the next week-month every time they find a new task that they don't do that frequently but thought they knew how to do.

Actually your analogy goes more the other way. My minivan is nothing like my suburban from when I was a kid except for having a steering wheel and a gas pedal. Pushbutton electric start, automatic transmission, power steering, automatic door locks, wireless key fob, bluetooth stereo comes on by itself without asking me, and probably next year it will be an electric vehicle with completely different mechanical characteristics. Basically, /bin/bash is the same and you might compare that to the steering wheel.

Cars changes a lot. Basics do not change, but it's the same for computers to. Keyboard, mouse, display, touchscreen, all this has been there for decades. Details though do change a lot. Compare the controls of 2 cars, one from the 70s, one from now, I'm quite sure you'll have much more buttons, a touchscreen, things to learn like how to disable airbags when needed, where to get the maintenance information. Even something like starting the car itself is likely to be different.

The insides, thank deities, would stay pretty much the same or even better (safer). If you opened the bonnet, you'd be in tears about how solid and sound everything is. You'd need to figure out where the doors are, though, and why some son of a gun decided that the steering wheel should protrude from the ceiling.

Asking the manufacturer would open the flood gates about how ungrateful you are about all the years put into designing the thing, and how other options were "confusing" to drivers, although said drivers should clearly be of some extraterrestrial species with a different set of sensory organs and appendages.