I think you misunderstand. Even back then, "PC" meant anything that roughly meant "MS-DOS compatible". (There was the stronger "IBM compatible", but you could u

I think you misunderstand. Even back then, "PC" meant anything that roughly meant "MS-DOS compatible". (There was the stronger "IBM compatible", but you could usually get very far even on "non-compatibles", so those were still called a "PC".) However, there was a multitude of completely different systems that had nothing to do with MS-DOS (or an x86-derived CPU) whatsoever: C64, Amiga, Atari ST, Amstrad/Schneider CPC and countless others. Some of them would maybe run CP/M. At least from some point in the 80s on, they would usually not be called "PCs".