Ironically, this is an example of where it is crucially important Oracle-Google case swings Google's way.
Currently, there are alternative implementations of Play Services that can be installed to replace Google's. However, if it is not fair use to use even the bare bones of an API definition without permission, then we can't even create a compatible implementation of such an API without the copyright holder's permission. In which case, we cannot replace Google Play services with anything else.
