You don't want a bunch of different car API system, you'd have to deal with so many issues like large (ongoing) investment and support from Apple and Google. Maybe you could get support for some things like AC control via Matter but car manufacturers would struggle to get proprietary features supported.
You just need car specific app icons to appear inside of the Apple and Google UIs. Since Cars reach EOL you don't want infotainment system to have to depend on iOS or Android SDKs/APIs since those will change and the cars will stop getting updates. You want a very loose coupling between the car and the mobile device.
To me that means progressive web apps (PWA). All it needs is some type of registry/discovery mechanism (that isn't Cloud based). You make the connection between your car and mobile device, the local app registry is scanned and the PWAs are installed.
You just need car specific app icons to appear inside of the Apple and Google UIs. Since Cars reach EOL you don't want infotainment system to have to depend on iOS or Android SDKs/APIs since those will change and the cars will stop getting updates. You want a very loose coupling between the car and the mobile device.
To me that means progressive web apps (PWA). All it needs is some type of registry/discovery mechanism (that isn't Cloud based). You make the connection between your car and mobile device, the local app registry is scanned and the PWAs are installed.