They probably know, but don't have the ultimate say in the matter. As others have said, having one screen as opposed to a variety of buttons and knobs that need to be wired is likely cheaper (even more when you don't really invest in proper software development).
I am not sure about the cost reasoning. The cars were equipped with all the buttons and knobs before the touchscreens. Then they started adding touchscreens - and it was the screens that were expensive, not the buttons that were already there.
But they went too far and moved everything to the screens. It's fine for big portion of the controls, but it's a big no-no for the controls you need to use while driving. And that's just a few buttons, to be honest.
Anyway, a decent design process would figure out. Seems like inner politics won instead.
> and it was the screens that were expensive, not the buttons that were already there.
The combination of a screen AND buttons is still more expensive than just a screen. If you are introducing a new component that is going to otherwise raise the cost of production, you will be looking for ways to reduce cost or, maybe more aptly, offset the cost of the new component.
With touch screens, you are presented with a unique option where the thing you introduce can be used to move all sorts of functionality to that would otherwise need its own hardware.
You also need to keep in mind that the physical buttons on older cars didn't need to be tied into a computer system as much as modern buttons.
