You forgot a massive step in-between: Digital art / Photoshop.
Which already vastly sped up art creation and made it easier (when you can just use special brushes instead of having to spend hours doing a pattern by hand).
And even though it’s a lot easier, you still need artists to produce proper products. Good artists and designers will keep their jobs in the foreseeable future, while more simple one-shot works can be done by AI.