If you're not a professional Lisp developer, an environment extensible in Lisp is not a plus :-)
I've had colleagues who were dedicated Emacs users, yet didn't know anything about Lisp.
This is not surprising; it's no different from Vim users who have never written or debugged a line of VimScript.
Rubbish. Speaking as someone with seventeen-odd years of professional C# experience and no professional Lisp experience, Emacs Lisp is both easier to learn than the Visual Studio SDK and, more importantly in the long run, far more likely to be worth the bother[1] for personal use cases.
Outclassed in what way?
Have you looked at LSP[1] and its support in Emacs[2], for instance?
That's not to mention things like SLIME and paredit for Lispy languages, or the integration of the rest of the Emacs ecosystem in to your development environment, the ability to develop and configure all these development tools in Lisp instead of being forced to switch to some other language, etc.
[1] - https://github.com/Microsoft/language-server-protocol/
[2] - https://github.com/emacs-lsp/lsp-mode/