If anything, the SCOTUS decision would seem to imply that generative AI transformations produce no additional creative contribution and therefore the original copyright holder has all rights to any derived AI works.

(IANAL)

that is a very good formulation of what I have been trying to say

but also probably not fully right

as far as I understand they avoid the decision of weather an AI can produce creative work by saying that the neither the AI nor it's owner/operator can claim ownership of copyright (which makes it de-facto public domain)

this wouldn't change anything wrt. derived work still having the original authors copyright

but it could change things wrt. parts in the derived work which by themself are not derived

The court avoided a decision of what the operator could have copyrighted because he said he was not the author.

That's a reasonable theory though it's stuck with the problem that any model will by its training be derivative of codebases that have incompatible licenses, and that in fact every single use of an LLM is therefore illegal (or at least tortious).