[minutillo]

I worked on a project (not cars, phones) where we replaced an older model that was operated through buttons and LEDs with a newer model that was just a giant multitouch screen. Surprisingly to me, it was way, way cheaper! And cheaper in multiple dimensions: the hardware buttons and LEDs weren't just more expensive, they implied a multi-step manufacturing and testing process on every unit. The touch screen was relatively standard and just came as an integrated assembly from a supplier.

We also went through a phase where we had a hybrid interface, the most common interactions done through hardware controls, everything else on the touch screen. There was always some level of regret associated with the hardware stuff, like we had some extra LED we never actually needed or just one more button would have been nice.