Actually, you got my upvote - emacs solved this problem 3 decades ago (!), runs everywhere, is easy to extend, and I'm gonna wager that emacs has far more users

Actually, you got my upvote - emacs solved this problem 3 decades ago (!), runs everywhere, is easy to extend, and I'm gonna wager that emacs has far more users than these bespoke terminal programs, which come and go. Countries will rise and fall, the sun will fade, and all that will remain are *nix and emacs.