Doubtful it will be based upon Android Auto since that is primarily a phone mirroring system similar to Carplay. It is likely an Android Automotive based system. Android Automotive is Google's infotainment OS. GM already has cars in production which use Android Automotive. There is nothing about Android Automotive which precludes the use of Carplay, and Carplay is already supported in other Android Automotive based infotainment systems. This is a GM decision to attempt to drive subscription revenues.

So why isn't GM getting out there and saying "don't worry, you can still use CarPlay"?

Unless the GM fork will prohibit it to maximize the data flowing to Google?

Because GM has made the decision to not support Carplay so they can drive subscription revenue. It has nothing to do with driving data to Google.

Anything made/modified by a car manufacturer will be absolute shit. Tesla and Rivian do a decent job from what I’ve heard but one could argue they are more software companies that make cars than the other way around. Also a huge complaint from users on both cars is they want CarPlay/Android Auto. Side note: how is Google so terrible at naming? (Auto/Automotive, it’s like they are trying to be confusing)

Car manufacturers are completely incompetent in this area, just give me a way to put my phone screen on the built in screen, just be a “dumb pipe”. This last the last gasp of failed arm of car makers (software) just like when the carriers lost that battle to Apple/Google.

Apple makes you jump through a large amount of hoops and approvals to allow CarPlay to work. Combine that with the incompetent manufacturers and you get this situation.

The manufacturers still have to make something to run on the screen. The owner may not have a phone, you're federally required to show a backup camera in all situations, etc etc etc.

Not defending anything here, just explaining that it's not as simple as "just" putting up a dumb pipeline.