I wonder if we struggle needlessly though in "regular software development" - and entire jobs or teams exist because we didn't find the right way to express things in a language. OTOH you could create lisp code that is so unique and weird in it's semantics that it's hard for a new team member to get onboard. But I've seen that done in C# too which allows you to have code that writes code at runtime (not as elegantly though!).
Yeah, writing your own language and self-modifying code can give you a lot of leverage, but usually they also make the code so much harder for other people to pick up that it's not worth it.
