It's been two years since Frozen was a box-office smash, but it seems as if Disney (NYSE:DIS) can't -- pardon the obvious movie reference -- let it go.

The popular full-length animated feature with its once infectious soundtrack keeps needling its way into Disney World's theme parks. Disney's Hollywood Studios -- the media giant's least visited Florida theme park -- has been turning to temporary Frozen-themed diversions to fill the void of gutted attractions as it makes room for the eventual rollout of Pixar Land and Star Wars Land.

There's a 30-minute sing-along show now featuring all of the songs that were earworms in 2013, and earlier this summer the park had a Frozen-themed parade and fireworks celebration.

The most ambitious incorporation of the franchise is taking shape at EPCOT -- Disney World's slowest-growing park -- where a more permanent boat ride will open next year in the World Showcase's Norway pavilion. It will replace the Maelstrom ride that closed last year.

Disney recently revealed that Frozen 2 is in the works. There isn't a firm release date, but online speculation points to 2018. That's pretty far away, but doing animation the right way takes time.

However, there has to be a fear that all of the initial hype behind Frozen and princess sisters Anna and Elsa is starting to fade. Anna and Elsa displaced Barbie as the most desired dolls in a National Retail Federation survey last year, but there will be some serious competition for holiday shoppers this time around. With Halloween in a few days, it probably won't be a surprise to see fewer Anna and Elsa costumed trick-or-treaters this season

It's not the only place where you may notice that Anna and Elsa aren't as popular as they used to be. Folks used to have to wait several hours in line for a meet-and-greet snapshot opportunity at Disney World. As the coaster chasers at Theme Park Review noticed last week, the wait to take a photo with Anna and Elsa was shorter than the adjacent greeting station for the Cinderella and Tangled princesses.

Arendelle has Frozen over! The line for the "other" princesses is longer than Anna & Elsa! pic.twitter.com/i2VdLw9Div — Theme Park Review (@ThemeParkReview) October 17, 2015

We could be getting burned out on the sisters. There was too much of a good thing, and as a result of being overexposed to the songs and characters of the movie, Disney has created another Who Wants to Be a Millionaire scenario. If that reference doesn't make sense, remember that hit quiz show that Disney had on ABC? It was doing great until it expanded it to as many as four prime-time slots. Viewers gave up as a result of the overexposure, and ABC had to pull the plug on the show.

There's a lot of Frozen going on at Disney World, and that may not be in the best interest of sustaining the franchise through the sequel's eventual release.