I don't see familiarity being with the touchscreen buttons being the issue. The issue is that actually touching a certain amount of pixels on a disembodied screen, while driving, while the car is in motion, is actually annoyingly difficult. No matter how attuned you are with them. I owned a Tesla for several years, and it never got better. It distracts the driver considerably. Unless they drastically increased the size of the interaction points on the screen and/or improved the gestures used to interact, I just don't see touchscreens being a good primary point of interaction between the driver and the car (at least until the driver really isn't regularly "driving" anymore).