So yes, it's totally possible for someone doing tech today to have never interacted with complex analog interfaces since being a little kid. Still unlikely for the next couple years, but possible.
A) The developer chose a touch screen to make the build easier and cheaper
B) The developer has never seen physical buttons
The answer is A)
2) Who says anything about touchscreens? Most touch interfaces your interact with aren't displays - they're capacitive buttons. Think your induction stove, or a powerbank, or any other random device you have to touch just right to turn on. Capacitive buttons are dumb pieces of solid-state electronics. Zero moving parts. Zero things to break (except maybe status LED that shines through them so you know where to touch). Cheap as dirt.
The future sucks because it wasn't created for improved quality or functionality - it was created because it was cheaper than the old-school way before it.