That's already been ruled on once.

A recent lawsuit challenged the human-authorship requirement in the context of works purportedly “authored” by AI. In June 2022, Stephen Thaler sued the Copyright Office for denying his application to register a visual artwork that he claims was authored “autonomously” by an AI program called the Creativity Machine. Dr. Thaler argued that human authorship is not required by the Copyright Act. On August 18, 2023, a federal district court granted summary judgment in favor of the Copyright Office. The court held that “human authorship is an essential part of a valid copyright claim,” reasoning that only human authors need copyright as an incentive to create works. Dr. Thaler has stated that he plans to appeal the decision.

Why would companies care about copyright of the output? The value is in the tool to create it. The whole issue to me revolves around the AI company profiting on it's service. A service built on a massive library of copyrighted works. It seems clear to me, a large portion of their revenue should go equally to the owners of the works in their database.