"We've done tons of user testing on this, and it turns out it doesn't work. Touch surfaces don't want to be vertical. It gives great demo but after a short period of time, you start to fatigue and after an extended period of time, your arm wants to fall off. it doesn't work, it's ergonomically terrible."
-Steve Jobs, 2010
https://www.businessinsider.com/steve-jobs-touch-screen-mac-...