IANAL, but in that case can I make an animated film about Cinderella? The story is in the public domain, but Disney have recent films.
By making a Cinderella film did Disney gained the right to block subsequent works based on it?
See the regular launching of "Sherlock" shows, and the multiple on-air concurrently.
Edit: Though Sherlock does have some limitations. Elements of the Sherlock stories introduced after 1922 are still copyrighted, but things from the vast majority of Doyle's stories are public domain and usable by anyone.
There's actually companies who create "Mockbusters" - movies with similar titles to the latest hits, to con people into buying them. They tend to walk a fine line, but they do OK (although they piss off a lot of customers).
I consider this practice just as unethical as hosting adult content on squatted domain misspellings of common sites.
Most mockbusters are made by 1-5 young animators, and they do the scripts and voice acting themselves. Pirates was notable for being one of the most expensive pieces of porn ever made (since it a real boat).