Have you run into that? I can't recall ever facing that issue. Seems very weird to strip down that much and then use a different editor. Do you remember if ed was missing in those machines?
> Do you remember if ed was missing in those machines
I had to laugh out loud. I couldn't imagine such a system, that wouldn't be POSIX compliant. So I looked it up, and indeed, it's entirely possible. Debian doesn't necessarily include it.
While not mandatory, vi is part of the POSIX commands. I mean you could use ed or even hack your way with awk, sed, and/or grep but no one wants to deal with that bullshit. And if you're installing vi you might as well install vim, right?
I've been on a lot of systems and can't remember a single instance of not having vi (though I do vim). So pretty rare, like you said