Emacs comes with extensive built in documentation. At the bottom it says hit C-h C-a which takes you to an about page which has various help links.

The GUI app as a menu bar, a standard gui feature that includes at the far right an entry entitled HELP under which one can find a manual, docs, a tutorial, a FAQ and various other options.

I definitely agree with you that nano is more intuitive and certainly much more beginner-friendly.

Just saying that vi at its most basic level isn't bad at all. The user only has to remember i,esc,:w,:q,:q! for basic editing. That's not much.

But I do agree that it would be nice if vi / vim would simply list those commands when starting the editor for those who have never used it or haven't used it in ages.

Indeed, nano's interface is easily discoverable. Vi(m) gives some hints, and emacs... the tutorial is kinda amazing but takes hours to get through. I can't really imagine a discoverable interface for vim that doesn't take up tons of real estate -- so the alternative is a cheat sheet tacked up next to your monitor