The Supreme Court declining to take up an issue is taking a position.
Now different circuits can take a different view of the same issue. This is a common reason why the Supreme Court will grant cert: to resolve a circuit split. Appeals court judges know this and have at times (allegedly) intentnionally split to force an issue to the Supreme Court.
Even without settling the issue appeals courts will look at how other circuits have ruled and be guided by their reasoning, generally. The fact that the Supreme Court declined to grant cert actually carries weight.
Moreover, SCOTUS does not decide issues, they decide cases.
Upjohn Co. v. United States, 449 U. S. 383, 386 (1981).the real issue is that the Thaler case was a different question: "Can AI be an author?" and the lower Court said no and SCOTUS left it along. But the question of "what is enough for the human to be the author" wasn't even part of the case. That is completely own checked.
Logically, I think there's a big difference between code which was produced from a simple generic prompt without other input vs code which was produced from a multiple complex prompts with large existing code as input.
When I'm feeding AI my code as input and it ends up producing new code which adheres to my architecture, my coding style and my detailed technical requirements, the copyright over the output should be mine since the code looks exactly like what I would have produced by hand, there is no creative input from the AI. It's just a code completion tool to save time.
I understand if someone leaves an LLM running as an agent for multiple days and it produces a whole bunch of code, then it's a very different process.
Fair point and worth being precise about. Cert denial is not meaningless: it leaves the lower court ruling intact, it signals the Court did not find the issue urgent enough to resolve now, and as you note, other circuits will look at the DC Circuit's reasoning. What it does not do is bind other circuits or establish Supreme Court precedent. The distinction matters here because if a Ninth Circuit case involving AI-generated code reaches a different conclusion, that circuit split would be live law regardless of the Thaler cert denial.