Before IBM PC computer's weren't particularly commonplace outside of ivory towers either.

You're forgetting the big three, all of which predated the 5150 PC - Commodore PET, Apple II, and TRS-80.

I went to a regional state university. We had an older IBM mainframe with a hypervisor and the students and faculty were all users on MUSIC/OS. This was in the early/mid 1990s.

That was a huge fraction of computing at the time. Before 1992 or so, the only people I was aware of that was into computers were all associated with a University. Typewriters were still actually very common.