The fact that they aren't going this way in the systems that __really__ matter seems to indicate that people don't really prefer touch screens.
Why would we port one of the compromises of the smartphone interface over to our car interface?
And yes, I know, dynamic is a trump card. It still sucks. Have you ever read Bret Victor's rant on it? http://worrydream.com/ABriefRantOnTheFutureOfInteractionDesi...
The actual point was that when it comes to safety/critical functions, we still prefer those mechanical mechanisms. Unless you're flying or driving with your iPhone, I think the point still stands.
I think the fact that safety critical fly-by-wire systems could operate without the mechanical interface yet designers choose to do so anyway underscores this point.
Do they?
A car's dashboard doesn't have to be small enough to fit in your pocket; it doesn't have a screen you want to look at constantly where there's a direct trade-off between screen space and physical keyboard space; a car's dashboard doesn't have limits of where buttons can be because you have to hold it around the edges without pressing the buttons accidentally.
I still hate typing with on-screen keyboards, I just grudgingly accept that for a given small phone size, I'd prefer more of it to be screen than keyboard. That doesn't at all mean I want my car to turn into an Android tablet because I prefer a touchscreen in the constraints of a pocket size device.