It isn't this completely. Hollywood is as fickle as a 5 year old wondering through Toys R Us. They latch onto what made money. The Texas Chainsaw Massacre and Halloween remakes made cash so that spurned Friday the 13th, Nightmare on Elm Street, Hellraizer remakes. Transformers was a huge hit, which not only spawn sequels but made Hollywood look at nostalga toys and option everything under the sun. GI Joe, Voltron, possible CGI Thundercats, Master of the Universe, etc. Even the success of Jumanji had them looking at board games which was followed by Zathura and there are even Monopoly, Candy Land, Battleship and Life movies in really early pre-production. Twilight is a hit so there are a ton of Vampire properties lifting. If/When "The Wolfman" comes out and is a hit you'll see new Universal Monster movies rebooting. Comic Book movies are even a part of this.
You still have original films being done in Dramas, Comedies, Thrillers its just that the Action/Summer Tentpoles have always kinda had this formula or else you wouldn't see pitches like "Its like Die Hard but on a Bus" being thrown around. Its just worse now because these properties have a tendancy to spawn amazing merchandising revenue.
