> The decision is not an infringement decision

> Supreme Court rules Andy Warhol’s Prince art is copyright infringement

And fair use is the main exemption to copyright, and that was decided here.

No it wasn't decided there. There is no analysis as to whether the image is infringing or not and it's not even a debate, because the warhol foundation admitted the pictures were substantially similar.

Even better for AI, then, if the supreme court was divided on whether such a small change is a valid use even with similarity assumed.