The zeitgeist is pregnant with new ideas. Our minds are much alike. Our world is so linked up, that we swim in the same pool. Subject to much the same stimuli, is it any surprise that we often originate similar creative ideas and insights?
If you feed a prompt into an AI image generating system such as Midjourney, who is the artist? Most people seem to want to give the credit to the AI, but, depending on how you go about it, I believe that the Prompter can claim to be the artist