Periodically there will be a rash of movies that follow a same theme or character. We'll get competing Robin Hoods one year and nothing but war movies or jewel heists the next.
One thing is certain: If, for example, one of the many failed attempts to resuscitate the western genre succeed we'll see screens filled with that decades-long abandoned story type.
In the world of Hollywood, being familiar and accessible equals big box office. Hence, all the Pulp Fictions and Blue Velvets of the world will never add up to the crowded world of Adam Sandler movies, films about talking animals and implausible romantic comedies.
When big success strikes, count on Hollywood to milk a concept for all it is worth.
Consider Star Wars, a classic of science fiction. By George Lucas' own admission it had elements of B-movie serials such as Flash Gordon, classic westerns and even the Japanese samurai movie The Hidden Fortress by director Akira Kurosawa.
What came in the wake of Star Wars was a long list of copycats, ranging from good and bad, successes and flops.
Battlestar Galactica was a TV show intended to tap into the Star Wars audience. It was successful enough to warrant a big-screen release of a beefed-up pilot episode, a spin-off set in the 1980s and the more recent revisionist take that ran on the SyFy network as well as a prequel, Caprica.
Star Wars' success led to some hits that, without a thirst for science fiction, might never have made it past the script stage: Alien, Saturn 3, and The Last Starfighter.
Disney's first ever PG venture, The Black Hole, aped Star Wars' style right down to the look of its B.O.B. robots.
There were also also-rans such as Battle Beyond the Stars, Galaxina, Jason of Star Command, Flash Gordon (the one with the Queen soundtrack) and Spacehunter: Adventures In The Forbidden Zone to name a few.
Skipping to other genres, Disney's The Lion King is, at times, nearly a shot-for-shot remake of the Japanese animated classic Kimba the White Lion.
The Terminator bore too close a resemblance to an Outer Limits scripts by famed science fiction writer Harlan Ellison. The litigious Ellison won a settlement and on-screen credit, likely aided by the fact that writer/director James Cameron admitted he was an influence.
Director Quentin Tarantino is at least upfront about how much of the 1987 Hong Kong movie City on Fire starring Chow Yun Fat he paid tribute to with his big break, Reservoir Dogs.
The animated Pixar film Cars, is -- and admittedly so -- basically a rewrite of the 1991 Michael J. Fox film Doc Hollywood. The shiny race cars scored far bigger, with a worldwide gross of roughly $462 billion (not counting all that themed merchandise), compared with Doc Hollywood's $55 million.