I've not done a lot of Go, but a former employer used it for all the back-end stuff, and they weren't using the standard modules for web stuff either (and it was at a time who didn't have a proper dependency management tooling so it was very tedious compares to modern languages).
> a former employer used it for all the back-end stuff, and they weren't using the standard modules for web stuff either
This might have been a long time ago but I can't think of much that you cant do. I've seen this behavior though on some project, but it was usually not about the stdlib's deficiencies but more so the developers lack of understanding what they're supposed to do and so revert to another lib.
It's never about stdlib “deficiency”, it's just that there are alternative ways of doing things in third party libraries and sometimes these alternatives are better than the original implementation which cannot evolve since it's in the standard library.