I think the takeaway is that an new editor has to be a platform, not just an app. Emacs was an OS for running Lisp code from the beginning, and it was trivially easy for end users who weren't Emacs developers to add their own extensions to it. VSCode has a rich enough API that JavaScript devs were able to do the same with it, and while I think Lisp >>> JS, there are a lot more JS devs out there who can add and tweak extensions, so it grew a huge fan base quickly.