Remember, Go is MIT-licensed. If things become too bound to Google, it can and will be forked. People thought it was the end of the world when multiple Java SDKs arose didn't they? (Not to say that didn't hurt Java, but the language survived).
I'm aware of TinyGo, but not any other forks
That being said, some pieces of the Go standard library have been copied across where it makes sense to (and works).