A car is largely a single purpose device. You always have the same few set of things you want to do in the car. Climate, Radio, Maps, etc. A touchscreen is a boneheaded interface for this device.
Imagine if your on-off lightswitches were touchscreens. If your stovetop interface was a touchscreen. If your refrigerator ice dispenser was a touchscreen (I've seen this). Completely moronic, every single one of them.