Visual Studio Code is not an IDE. It's just a bad named Editor
It also has some refactorings and even a console and plugins. What do you think it lacks to be an IDE?
Note that it's also also in early stages atm.
I haven't used Visual Studio Code enough to be able to speak to it specifically, but editors like Atom and Sublime can be outfitted to basically be IDEs.
I can actually do more with Atom now than i could with Webstorm just a year ago.
If you don't count the plugins, it's barely even an editor (even syntax highlighting is a plugin).
And I agree with the last part as well. Properly configured Emacs and vim can be used as IDEs, however they can also be used as editors.
Plus, IntelliJ and Eclipse BOTH implement ALL of their functionality as plugins. It's just that they come with a default set of plugins pre-installed.