TL;DR
- Efforts like Graphene OS face increasing pressure from apps that refuse to run on non-standard Android.
- The custom ROM project characterizes Google’s approach to device attestation as incomplete and flawed.
- Graphene OS is prepared to take legal action if Google won’t let it pass Play Integrity checks.
Afaik GPL 2 would be stopping google from making android closed source anyway, unless I got something wrong about the license terms. But if anything that supports your argument. The main reason google is generally supportive of open source is that they recognize that they benefit from it. The moment that changes, google will try their best to close off anything it can (granted I don’t think it’s that likely to change, but they’re already abusing their position plenty).