Bear in mind that IBM has been making computers — and terminology — since the 1950s. They invented hard drives. So it seems wrong to say their terminology has “diverged”…from what?
IBM terminals like the 3270 operate almost like a web browser, with form fields implemented by the terminal. The computer sends a page of text, you use the terminal to edit it, and you submit data back. That’s why you have to move around the screen to type things in the right place, and thus why the editor has “line commands”.
There were no words for this stuff. People just made it up, and it took years for something to emerge as the de facto standard term for a collection of data persistently stored.
There's an interesting parallel with the emacs editor. Operations we now universally call "Cut" and "Paste" are "Kill" and "Yank". The better terms won out and emacs is stuck with Ctrl-K and Ctrl-Y as not-so-intuitive mnemonics for cut and paste.
I actually don't think they won out. Mindshare maybe, but I use kill and yank on macOS all the time. In fact, since they are enabled by default, I use Emacs keybindings all the time and everywhere on my Mac. Even the password entry screen in macos has Emacs keybindings.
I always thought that Apple saw the superiority in these bindings that they have them included by default.
As much as I love emacs, I think cut and paste is better metaphor for text editing than kill and yank. Once the key combos are part of muscle memory, the value of mnemonics goes down, but they're very useful for adoption. This is an unfortunate barrier for emacs beginners. Even though the usual CUA keystrokes are available (and even the defaults on some popular starter configurations), the terminology creates some friction when reading the docs.
I agree the semantics are strictly superior though.
IBM terminals like the 3270 operate almost like a web browser, with form fields implemented by the terminal. The computer sends a page of text, you use the terminal to edit it, and you submit data back. That’s why you have to move around the screen to type things in the right place, and thus why the editor has “line commands”.