As an attorney (and this is not legal advice), I would argue--and the U.S. Copyright Office has already stated--that machine-generated content is not copyrightable, because it's not a form of human creative expression. https://www.copyright.gov/ai/Copyright-and-Artificial-Intell... ("Copyright does not extend to purely AI-generated material, or material where there is insufficient human control over the expressive elements.")

That said, the inquiry doesn't there. What happens next after the content is generated matters. If human creativity is then applied to the output such that it transforms it into something the machine didn't generate itself, then the resulting product might be copyrightable. See Section F on page 24 of the Report.

Consider that a dictionary contains words that aren't copyrightable; but the selection of words an author select to write a novel constitutes a copyrightable work. It's just that in this case, the author is creatively constructing from much larger components than words.

Lots of questions then obviously follow, like how much and what kind of transformation needs to be applied. But I think this is probably where the law is headed.