As you alluded to, the answer is they don't care. Car companies look at software like it's any other line item on the BOM. Like a bolt or a gasket: Source it as cheaply as possible and spoon it onto the product somewhere on the assembly line. I see fit-and-polish mistakes all the time in car infotainment. Text that can't handle unicode, icons that are misaligned by 1 or more pixels, connections dropping and coming back, audio mixing problems, things drawing outside their "windows." Nobody cares--they get to the drop dead date when the software needs to be on the assembly line, hand it over, and start flashing devices.
I agree with you, and I can also easily imagine how this comes about with the software teams or contracted companies that do the infotainment system being completely different people from those who design the rest of the car.
But it was still a surprise to see this a lack of attention to detail in the infotainment system, in a car where the brand itself is all about giving a lot of attention to detail in everything else that's visible, the comfortable mouldings, pleasant interior lighting, different kinds of cup holders, nice place to wirelessly charge your phones, seat controls and sensors, etc.
