Daniele Sluijters says:
People make fun of #emacs calling it an OS, but why do you call #Xcode that's actually bigger than #osx an IDE?
— Daniele Sluijters (@daenney) August 3, 2015
He has a point but I don’t think the notion of Emacs as an OS is a bad one. I came for the Lisp support but I’ve come to think of Emacs as a Lisp Machine-like operating system where all the code is available and can be changed on the fly to exactly suit my requirements.
Emacers famously move towards doing as much as possible inside Emacs. Many consider it a cache miss if they have to leave Emacs for some task. I’m not hardcore enough to use eww for all my browsing but other than Safari and (temporarily) Mail.app, I spend virtually all my tube time in Emacs. That tendency is the realization of Emacs as an operating system. The transformation of Emacs into an OS is ongoing. Indeed, we recently acquired a window manager.
The old joke about Emacs being a good OS needing only a decent editor may be stale but it does contain a germ of truth. Except for the editor part; I like the editor.