Earlier quoted context omitted.
And yet you still have a "command prompt" so that you can run your DOS programs as well as "compatibility mode" so that older applications can run on the post-XP systems.
"Command prompt", i.e. terminal, is what makes you toy a computer. If you don't have one, it's still a toy. MS did a lot to turn their lame "DOS command prompt" into a command line terminal; not enough, but a lot. So no, "command prompt" has nothing to do with DOS. You can run DOS programs from the GUI as well.
The first computers dealt with input via switches and levers. I don't think anyone would call the Colossus[0] a toy, and it had nothing resembling the command prompt that we know today.