That may be true, but in this case the relevant parties to be persuaded are federal appellate judges before it can fairly be said that reality has changed on th

That may be true, but in this case the relevant parties to be persuaded are federal appellate judges before it can fairly be said that reality has changed on the ground. How likely they are to be persuaded by a position that has no apparent basis in the statutory text is a real question. As far as I can tell, no one making these rather unusual claims has even tried to outline such an argument. Why should anyone be persuaded by a legal position that has internal logic that has never been explicated anywhere? If lawyer A writes to lawyer B claiming that B's client is creating a derivative work but cannot explain why, lawyer B is more than justified in laughing them to scorn. Even if B did create a derivative work according to some unknown and unheard of legal argument acceptable to the courts, fair use could apply anyway. But one can hardly begin to look at the fair use factors if lawyer A could not even identify how a legally cognizable derivative work is being created in the first place.