This would be a great idea but as I understand it, Android Auto and CarPlay are very explicitly tied into the auto manufacturers systems in a way that would likely require a group that builds the open source mobile auto platform to be certified and integrated with auto manufacturers systems.
This would be costly, and without the initial user base, unlikely to take off as manufacturers don’t like giving their data to other systems. Toyota held out a long time on Android auto for exactly that reason: not wanting Google to get access to their systems.
I like the idea, but I think the only for it to happen would be if an aftermarket headunit manufacturer were to build something that integrates with such a system. But that would be a very small user base and also unlikely to happen.
This was the only reason I used Zune music back in the day. Then they discontinued this feature but I had windows phone so Xbox music wasn’t bad. Plus they had these promos where I was able to get several years of service for extremely cheap. Then they shutdown the service all together but offered existing subscribers a refund in the form of Microsoft store credit. They gave me fill value of all the years of service so I bought of Surface Pro with an extended warranty. Then that died and they refused to honor the warranty as they dragged on my complaint until the warranty expired and didn’t resolve the issue, ultimately claiming I’m not under warranty.
I’m quite removed from Microsoft products now…