People don't create perfection. If you hired a graphic artist to create an image and gave them the same prompt, there would almost certainly be things that you'd want changed.
So far, AI seems to do very well with ambiguous prompts that give it enough latitude to "do what it does best". Areas of an image where there is a lot of source images to work from end up great, while areas where there is little - or where there is a lot of variability in the source images - don't do so well.
Maybe we'll get to the point where AI generates acceptable (or even excellent) results the first time, every time. Maybe it'll even be soon, but we're not there yet. For now, AI is a very useful tool that can multiply the productivity of professionals and let amateurs fake being entry-level.
For now at least, there is a huge gap between "entry level" and "professional". Because of that, we'll need professionals for the foreseeable future.