I think you're wrong to presume that the TUI would have remained static at DOS 3.3 or sh as it was in the mid 80's - something like fish would have evolved anyh

I think you're wrong to presume that the TUI would have remained static at DOS 3.3 or sh as it was in the mid 80's - something like fish would have evolved anyhow, menu driven TUI's can be amazing, and efficient. Marriott uses a TUI based PMS at most of their hotels, it has a learning curve like a hockey stick, but once you learn it, you can literally check a guest in 5+ min faster than using Lightspeed (what most Sheratons used), its just that much faster - a big part of that is typeahead, you dont have to wait for the screen to populate to make the next selection, something that isnt true for GUI's.