Guardians of the Galaxy, Harry Potter, Fast and Furious, Frozen — why can’t theme parks come up with new attractions based on original ideas?

While some fans might long for the days when Disney opened new rides and shows such as the Country Bear Jamboree and the Haunted Mansion, with no movie or TV tie-ins, theme parks love the promotional boost they get from opening new rides and shows with a built-in fan base. When you’re spending tens or hundreds of millions of dollars on a new attraction, you want every advantage you can get.

Yet Universal is opening a new water theme park in Orlando based not on a movie, TV show, or toy line, but on its own, original story. Universal’s theme park designers have concocted a story about the made-up Waturi people of the South Pacific to bring life to its new Volcano Bay theme park at the Universal Orlando Resort.

For years, Universal’s theme park motto was “Ride the Movies,” and it’s been nearly 20 years since the Universal theme parks developed a major attraction that wasn’t based on a movie, television show or at least a popular book.

Universal Orlando’s Islands of Adventure theme park originally included a “Lost Continent” land that drew from ancient and medieval-themed mythology, but in 2010 Universal converted almost all of that land into its first Wizarding World of Harry Potter.

According to Universal’s back story for the park, the Waturi traveled via outrigger canoes across the South Pacific — from Rapa Nui (Easter Island) to Bali — before discovering the island of Volcano Bay, where they finally settled, creating a home in the style of the places they’d visited.

It’s a cute story, but one that easily can be ignored by anyone who just wants to get on the water slides or lounge by the many pools. Yet Universal is hoping that the extra attention to story and decor will attract theme park fans that might otherwise opt for Disney’s also well-decorated and themed Blizzard Beach and Typhoon Lagoon water parks.

For Volcano Bay, Universal had decorated the water park with a variety of South Seas motifs, including Tahitian, Maori, and even Thai influences.

Volcano Bay’s big competition for attention this summer hails from Disney, but it’s not one of those water parks, and yes, Typhoon Lagoon was getting a major refurbishment and some new attractions. It’s Pandora — The World of Avatar at Disney’s Animal Kingdom.

That new Walt Disney World land is based on a film — James Cameron’s 2009 blockbuster, “Avatar.” But it might as well be based on a theme park-original story given how few fans seem to feel any passionate connection to that story of giant blue nature-lovers on a world being invaded by greedy human business people.

Disney is also banking on the sequels to “Avatar,” all ready in pre-production with scripts that actress Sigourney Weaver called “incredible.”

Based on early booking reports from Orlando-area travel pros, Avatar isn’t bringing fans to the park the way that Harry Potter did for Universal, or even how Frozen and Cars did for Disney in recent years.

Still, Disney reportedly spent approximately $1 billion developing Pandora, and while Universal is not said to have spent anywhere near that on Volcano Bay, the park clearly represents an investment of many millions of dollars.

For the two biggest companies in the theme park business to make the money they expect on these attractions, they will need fans to embrace them without the help of an already widely beloved entertainment franchise.

If they do, maybe that will inspire theme parks to turn loose their designers to develop more original ideas. Now wouldn’t that be fun?