[fiddlerwoaroof]

How about the existence of major pieces of software written in Common Lisp? For example, American Express fraud detection was and maybe still is done by a CL program. Google Flights uses ITA Software’s CL flight search system. Emacs is widely used and contains a lot of lisp.

I think basically no languages have failed or succeeded for technical reasons: generally, marketing and inertia explains the tech stack better than DX or theoretical superiority.