I don’t doubt they were rotoscopes. I just doubted they were originally shot with the intention to re-use them in other features later on. But since it turned out they could be re-used, they were. It’s still kinda cheap.
But I have no place to speak. I can’t count the number of stock shots I’ve licensed for various TV shows over the past thirteen years. Even for locations where we were actually shooting and just didn’t bother to shoot an establishing shot.