This memo in particular emphasizes the existing guidance the US government has issued around not expiring passwords. If you are a federal agency, you can have (and are in fact encouraged to have!) users with passwords that are unchanged for years.
Edit: it's worth pointing out that the memo does a great job of laying this out. I work in security, so possibly there's some curse of knowledge at play, but I found the blog post explainer to be less clear than the memo it is explaining...