Can’t you just add a “driving mode” that changes the view or displays a different view to the phone?

If you externalise the smarts, all you need is external input and output support which all exists. Then any car can have better GPS.

This way, I need a car that specifically has this extra cruft and probably can’t get upgrades easily. It’s the car equivalent to a smart TV.

That's effectively what carplay is though. There are no smarts in the car, just some protocol to display video output and communicate back touch inputs. All the presentation, etc. is on the phone so that when you upgrade your phone you get the latest car interface as well. The protocol is stable, so your car can be stagnant but the experience still continues to improve as your phone does.

Android Auto was available as an app without need any hardware, but it's gone.