>It's pretty trivial to recreate famous works like the Mona Lisa or Starry Night or Monet's Water Lily Pond.

A recreation of a piece of art does not mean a copy, I've personally seen hundreds of recreations of Edvard Munch's 'The Scream', all of them perfectly legal.

Even in a massively overtrained model, it is practically impossible to create a 1:1 copy of a piece of art the model was trained upon.

And of course that would be a pointless exercise to begin with, why would anyone want to generate 1:1 copies (or anything near that) of existing images ?

The whole 'magic' of Stable Diffusion is that you can create new works of art in the combined styles of art, photography etc that it has been trained on.