I think you're missing the point of people saying that they want CarPlay/Android Auto. People don't want another system, they want another set of controls, screen, speakers and charging dock for their smartphone. They already have an intimate relationship with their phone. Phones are addictive. It's where people get their dopamine rushes from social media, sms and games. You can't compete with that. Even if someone is driving many, many hours per day, their relationship with their car will never be as strong as it is with their phone, despite the fact that they've paid more than 20x for the car. The more you try to compete with those systems on a feature-by-feature basis and try to impose your brand, the more you're going to lose. The more you design your system to be a natural extension of their phone, with as much looking and feeling like the phone's interface as possible, the more well received it will be. CarPlay and Android Auto are the easy answer to making it as similar as possible.

Trying to understand the issue from a technical or UX perspective is going to lead to a whole lot of failure. You need to understand the psychology. And what auto manufacturers resisting CarPlay and Android Auto are doing is akin to hitting on people in a committed relationship. It makes them angry and want to reject you, not dump their significant other. Accept that you'll never be more than friends and build the best platonic relationship you can, no matter how much you want them to love you.