This is what the Android Common Kernel is, it already exists as a Linux fork to provide a stable ABI. They are creating their alternative kernel Zircon so they

This is what the Android Common Kernel is, it already exists as a Linux fork to provide a stable ABI. They are creating their alternative kernel Zircon so they can instead have a less free ecosystem like Apple, steps to do this may be deprecating open-source Android and continuing on with Google Play Services mandatory closed-source fork.