Fair use doctrine has a lot of nuanced case law. I believe fair use has to be "transformative" upon the original, and it also cannot act as a market substitute

Fair use doctrine has a lot of nuanced case law. I believe fair use has to be "transformative" upon the original, and it also cannot act as a market substitute for the original. E.g. if a new movie is substantially the same as an old movie, not transformative (e.g. like commentary or parody) and could reasonably be viewed as a market substitute for the old movie, then it'd probably be considered unfair use.