For instance some people have always had more advanced editing programs than others, or different performance levels of their hardware to run the software which makes/allows the final product to be more effortless than the mainstream by far. Effectively with significantly different output from the same input, all unique no matter how you try to make all your PC's run the same, kind of like a video game where you get better resolution or framerate when you have more advanced hardware and/or software. Sometimes just a little bit better which could be considered incremental. Sometimes much more than that which can astound as a major leap.

When somebody comes along with a much more powerful hardware or software arrangement to output the same class of data, is it supposed to kick them out just because it's a major milestone that can not be ignored?

You could start with something like a completely original watercolor, and very well be using the exact same PC but naturally get two distinct printouts from the same digital file simply from using two different printers. With more significant differences than if one would have been touched by AI and the other one not.

Regardless of copyright, the person who submits the winning image to an image contest should really be the one to take home the prize.