I didn't understand much of you said but it sounded mathy so I'm going to reply with a counterexample, just look up on youtube Russ Cox solving AoC with Acme and tell me that's not impressive!

By the way, using a GUI doesn't automatically using the mouse for everything, think of GVim or Emacs. the problem with terminal emulators is the emulating part, where they are forced to comply with the idiotic rules from the '70s.