That's not what is commonly meant by "TUI". But as you mentioned, these old UNIX tools were really meant to be used with output printed to paper, which formed p

That's not what is commonly meant by "TUI". But as you mentioned, these old UNIX tools were really meant to be used with output printed to paper, which formed part of their "user interface": With CRT terminals, they actually become less usable, since anything that scrolls off the screen gets lost (even today in a terminal window, there is usually a limit to how far you can scroll back). And I feel like all those UNIX lovers going on and on about how efficient command line tools are don't get this at all. For a command like "replace 'foo' with 'bar' in lines 1237-1451" to make sense, you either need superhuman memory, or a printout nearby. And if you don't use it every day, you'll also need to look up the exact syntax for that command. PCs running MS-DOS might have been less powerful than UNIX machines, but they got really good, discoverable text user interfaces that took advantage of the hardware available, and could access that hardware in the most direct way. The best that is available now on Linux are really just pale imitations, and have to go through layers of terminal libraries and ugly hacks, like connecting to the X server in order to get the state of modifier keys that the terminal doesn't send.