I heard a very simple explanation from a car engineer involved with setting up the factory pipelines. Each button has a limited life time, each button has a particular chance of being doa, or a particular chance of being fitted badly, some fail prematurely.

All of this leads to an increase in “failures” in seperate steps of the manufacturing pipeline, assembly of dashboard, assembly of car, after the car is completed, after it is shipped to dealer, and after the new owner picks it up, during the lifetime of the car. Each of those moments occurs a significantly increased cost of replacing the button.

By simply removing buttons and knobs, this source of failure rate goes down and it appears cheaper. It is also the reason behind going from 4 buttons for the windows to 3 (left, right, and a toggle for front/rear)

According to him the monetary savings were significant enough to proceed with it. Personally, I wish they wouldn’t. But I believed the numbers.