The real kink in that application of derivative work to me is the entire dataset goes into the model and is to some vanishingly small extent is used in every output how can we meaningfully assign ownership through that transition and mixing. And when we do how do we do it without exacerbating the extant problem of copyright in art? We already can't use characters and settings made during out own lifetimes in our own expression because Disney got life + 70 through Congress.