What you say applies to slop, not anyone using AI seriously. Which is a small minority, but still.
If you put in a lot of work, you might not be the author of the realization but you are author of the concept (assuming it is not trivial). Why should you not be able to protect your ideas?
What is the status of a movie director compared to the actors?
Who is usually mentioned when discussing whether the movie was well crafted or not?
The best actor cannot save a shitty plot.