Higher-end units are using a "control knob" to navigate on the screen. "Touching" is for "lower-end" vehicles. So, as a matter of fact, yes, you can have _one_

Higher-end units are using a "control knob" to navigate on the screen. "Touching" is for "lower-end" vehicles. So, as a matter of fact, yes, you can have _one_ button for every car feature.