To repeat: "It seems that language-culturally, Go authors are fine with breaking changes". I just chose x as examples of near-stdlib, as opposed to appearing to complain about some library made by some random person with skill issues or who had a reasonable opinion that since almost nobody uses the library, it's OK to break compat. Protobuf is another. (not to mention the GCP libraries, that both break and move URLs, and/or get deprecated for a rewrite every Friday)

The standard library not breaking is table stakes for a language, so I find it hard to give credit to Go specifically for table stakes.

And it's not like Go standard library is not a bit messy. As any library would be in order to maintain compatibility. E.g. net.Dialer has Timeout (and Deadline), but it also has DialContext, introduced later.

If the Go standard library had managed to maintain table stakes compatibility without collecting cruft, that'd be more impressive. But as those are contradictory requirements in practice, we shouldn't expect that of any language.