Lem looks great and I wish we all could simply move there, I personally, am not married to a concrete implementation of Emacs, I just love the idea of an editor built atop a Lisp REPL; I don't think I ever could use a computer without having it.

However, what then we'd do with nearly half-a-century history of Emacs? There are so many packages out there - it's insane to ever think we'd have to re-implement all that ginormous constellation of functionality in Common Lisp. Until we can find some quick way to translate them there, I honestly don't see any practical possibility for the migration.

Who knows, maybe agents will get so good and someone will eventually figure out a path; until then, Emacs is to remain - with all the good and bad parts.