Despite widely reported misinformation, seeming to originate from Reuters, copyright protection for generated works is not dead, not even close. A much more accurate understanding of the case and what it actually means can come from simply reading the actual ruling (which isn't eligible for copyright because it's a creation of the US government).
https://media.cadc.uscourts.gov/opinions/docs/2025/03/23-5233.pdf
TL;DR: The case doesn't matter because Thaler deliberately avoided having the court answer if "AI" generated works were eligible for copyright, making the court answer a completely different, and much stupider, question not applicable to anything else. Thaler's arguments were as well thought out and based in law as trying to argue his way out of a traffic stop by claiming he was "boating under the Articles of Confederation", showing he had no idea how existing IP law works on even a basic level, but really wanting to make a name for himself as the man who changed everything.
The problem with claiming the case determined the eligibility of works made with "AI" is that Thaler expressly denied he was the author, and instead sought to claim that a machine was the author and a work needing to be of human authorship to be eligible for copyright was unconstitutional, but he still owned the copyright (it's as stupid as it sounds). At no point did Thaler claim he authored the work using the generator, and thus the court never ruled on if that was or could be the case, let alone if such was eligible for copyright. His loss stems purely from his own self-expressed non-authorship allowing the office, and subsequently the courts to skip any determinations on authorship and skip straight to a denial on the basis that he wasn't the author. The court also found that even if Thaler's argument was somehow correct, the copyright wouldn't even belong to Thaler, but to the computer he asserted created it, and there was no way for him to get the computer to hand him the copyright (e.g., lacking the ability to sign legal documents, it never signed a work for hire contract, and can not sign a contract trading away its ownership for an arbitrarily large amount of money). Thus even if the court were persuaded on his argument about the Constitutionality of fundemental IP law, his initial copyright filing still would not be valid, and would be instead be attempted theft.
This narrow ruling does not prevent a future court from affirming that "AI" generated art can be of human authorship and thus eligible for copyright, only that Thaler denied this work was and thus the court held it wasn't. Indeed, the position (also not eligible for copyright) of the United States Copyright Office that denied Thaler in the first place (which previous rulings have agreed with) is that "Where AI merely assists an author in the creative process, its use does not change the copyrightability of the output". What the line for assisted is is unclear. While the position of the Copyright Office overall takes a dim view on prompts alone qualifying, it barely explores the concept such as a fixed seed (largely because Midjourney's implementation is awful and that was the only generator considered edit: and I recall Midjourney was one of the ones that randomly added ethnicities to user prompts rather than give what they asked for to "combat racism" and that was why fixed seed didn't work properly), let alone tools that have been available to the public for what is now years such as LoRA selection and creation, controlnet (including mistoline), regional modification, etc. that allow the human author full control over the final result.
One final note is that SCotUS refusing to take up a case in no way binds future courts of other districts, or prevents it from taking up a case on the subject in the future. Indeed, SCotUS rejects most cases seeking cert and normally only takes up cases when the district courts disagree (a "circuit split"). They also normally avoid taking up cases with totally and deliberately incompetent defense, and only have really only done so during a period of intense and open corruption where one of the "Justices" directly helped pass the law under consideration and the others were publicly known to be acting under coercion. SCotUS may still, eventually, take up a case on the copyright eligibility of "AI" works. However, it is almost certain that case will be much better argued than Thaler's self destruction.
p.s., While I'm explaining all this and since it's also widely misreported by people who don't understand law: Kadrey v. Meta, the case against Facebook's mass piracy for training, was tossed out on summary judgement because the party('s attorney) failed to fully state a claim, which is required in copyright lawsuits. The dismissal was explicitly (per the Judge's own ruling) not a ruling on or approval of Facebook's actions but simply something the court had to do because the filing was critically defective. Essentially their lawyer did the legal equivalent of getting a 0 on a test by not signing and dating the paper before turning it in.