A person is also very much adding rose bushes and story beats to their internal databases. You learn to paint by copying other painters, adding their techniques to a database. You learn to write by reading other authors, adding their techniques to a database. Original styles/compositions are ultimately just a rehashing of countless tiny components from other works.
An AI understands what they see, otherwise they wouldn’t be able to generate a “rose bush” when you ask for one. It’s an understanding based on a vector space of token sequence weights, but unless you can describe the actual mechanism of human thought beyond vague concepts like “inspiration”, I don’t see any reason to assume that our understanding is not just a much more sophisticated version of the same mechanism.
The difference is that we’re a black box, AI less so. We have a better understanding of how AI generates content than how the meat of our brain generates content. Our ignorance, and use of vague romantic words like “inspiration” and “understanding”, is absolutely not proof that we’re fundamentally different in mechanism.