“Seeing more stuff” makes it harder to find the one thing you want without taking your eyes off the road. A touchscreen or similar interface in a car allows you to maintain a minimal set of buttons and controls for access to essential functionality while driving, while keeping the complex and infrequently-used stuff hidden in the touchscreen for access while stopped (when you have as much time as you need to search through the interface finding the thing you want).

I agree that putting controls which you need to use while driving behind a touchscreen is not an optimal choice.