I would tend to favor an approach based on support commitment and distance from the core functionality. Cars are really two products, a pretty mature transportation system and (these days) a low-end entertainment/map system which a cheap Android vendor would be ashamed to ship. They’re used to supporting the mechanical side for ages but software support is much rockier.
If the vendors had to support full functionality on those appliance-like systems at no cost for the 10-20 year service life of the vehicle, it’d just be CarPlay/Android Auto because they know that’s not their strength. “Smart” refrigerators would similarly not be common if they couldn’t orphan it after a year or two.