Maybe because everything is bundled and platformized. If Google release self-driving car software, they may force to use their entertainment and UI systems for

Maybe because everything is bundled and platformized. If Google release self-driving car software, they may force to use their entertainment and UI systems for cars too. Then it means better integration with Android and Google cloud services (i.e. maps and related services), interoperability with Google's home automation. At some point iOS may become isolated from this infrastructure completely.