Just as some off-the-top history, MS-DOS was clearly obsolete, but it hung around for like 10 years too long because people couldn't quit it. It was a DOSSY DOS world.

"Protected Mode DOS" went through the IBM/MS gristmill and became OS/2, which was a compromised product in a lot of ways. Then Windows (still mostly a DOS program) got a little traction, and Microsoft had hired Dave Cutler to write a real OS. And David overthrew Goliath and the rest is history. On topic, nobody really wanted protected-mode DOS or CP/M etc.