I agree entirely re: little originality in Hollywood, but it *is* possible that this was a case of unconscious plagiarism. Sometimes stuff just sticks in your head, and years later it pops out as seemingly something original.
One of my profs in college -- a very well-regarded writer -- said that she unwittingly included in one of her stories a phrase that an even better writer had used (to describe foliage); only when she re-read his work later did she realize that she had unconsciously ripped him off. She told us this in part to remind us to be as vigilant as possible -- and also to tell us that it just happens sometimes, despite the best intentions, bc we're bombarded by so *much* material every day that we inadvertently keep some but not all (as in, we keep the great line but not the attribution).
Also, with billions of people on the planet, two (or more) people are going to come up with the same idea. Years ago, a famous member of SNL made a joke on air that I had made (he was funnier, of course) -- and there's no way that he ripped me off, no way that my little joke somehow traveled to him. We both just had the same response to a certain current event.