It also uses cgo internally for that task. https://github.com/golang/go/blob/2a029b3f26169be7c89cb2cdcc...
https://golang.org/pkg/os/
https://docs.microsoft.com/en-us/windows/win32/api/
Yes. I never cared for cgo, and I'd say most don't.
>and for Go libraries that don't call into OS APIs.
Or that have those APIs wrapped for different conventions. So? This still leaves billions of possible apps, and thousands of existing ones...