Because there is no demand for it to be fully handled by AI. Nobody is denying that parts will be handled by AI but that’s also you moving the goal post.
What makes you say that? You think people like paying professionals to edit their videos? Surely some do, but everyone?
Coraline is a claymation movie made by hand, and Wildwood is coming out. But it’s because a cofounder of Nike loves stop motion animation. Despite critical acclaim these movies don’t make money. Just like we don’t have masterwork marble sculpture makers anymore. I have serious doubts anyone will surpass the works of Michaelangelo in the next hundred years; maybe a thousand.