It's possible to have all kinds of differences while also having a standard framework or paradigm. One just hasn't gelled yet.
The first cars didn't all agree on even the most basic controls like steering, braking, accellerating. Ony after some time did the currently universal framework establish.
The same thing could happen to car computer interfaces. Some sort of paradigm evolves for some common elements that all car consoles have, and that framework of recognizable bits is good enough.
The cars would all still be different as they all are now. I can easily switch from my manual transmission 4wd 4runner to my gf's prius, and I only joke about being baffled by the pushbutton ignition, missing clutch pedal, and the ridiculous shift lever on the dash for comic effect.
The important paradigms of operating different vehicles are either the same or are recognizable by some same cues, even though I have two shifting levers and 3 pedals and they all do direct physical things, and she only has 2 pedals and 1 lever and they're all just fancy light switches, and some cars have cruise control and backup cameras and rear wipers and other cars don't even have those things in any form let along a different form.
On the other hand, she can't drive my 4runner at all. So, maybe that's a point against my own argument. That there are already differences even in the basic controls that make it difficult or impossible for someone used to one vehicle to operate some others, long before any car computers came along, and so, who cares if the car computers are standardized or not?