Insufficient pedantry detected.

The PC platform is an extension of IBM’s Personal Computer architecture, which was not a description of what it was so much as it was literally the brand name. It’s long since been forgotten that this is now a shorthand, and the full name of the platform arguably ought to be PC Compatible. Unless you bought your machine from IBM, anyway, which these days would be quite the trick.

Being PC compatible was a big deal back when the original PC was also a big deal. Probably slightly less so now, since it’s the assumed default.

It should go without saying that the original IBM PC, model 5150, did not run Windows… Because Windows did not yet exist. It didn’t even necessarily run the then-nascent PC-DOS provided by Microsoft, because IBM also supported running CP/M and and UCSD Pascal on it.

The whole Windows-as-default thing didn’t happen until well after the appeal of the PC specification had escaped containment at IBM and x86 had handily taken over the desktop computing world.

A personal computer is basically anything you can stick on your desk (or lap) and doesn’t require hooking up to a mainframe to run. But a Personal Computer, capital P and C, implies an x86 compatible platform with architecture designed such that it is technically still capable of running all those decades old 8086 programs and operating systems. (Just, several orders of magnitude faster than their designers ever envisioned, and probably only by sticking your UEFI BIOS in legacy mode first.)