I do hope at some point we can get over this apparently undying urge some people on this board have to be constantly yelling, "PROPERTY X ISN'T SUCCESSFUL BY MY METRICS THAT I WILL STICK TO DOGGEDLY, THEREFORE WHY THIS, RAH RAH, OLD MAN YELLS AT CLOUD, ETC!" But since it seems like we're a ways away from that...
Avatar, the movie franchise, doesn't have a huge merchandising or "cultural" footprint because it's not about the characters. There ARE no iconic characters, stories, etc. that you see in traditional massive franchises, nor are there crazy plot twists or anything else that can create huge buzz. No one that will seem like a fun character to dress up as on Halloween (sigh). From that perspective, it can be easy and tempting to make it seem like a flop on some level, or an odd choice to base a franchise off of in any capacity.
BUT
Pandora is a compelling environment (and compelling theatrical experience), which is why the movie has made gangbusters box office in spite of the fact that its characters and plot aren't traditionally iconic, and why Pandora works well as a theme park environment.
For all the digital ink spilled on the internet about all of the importance of story to theme parks, particularly Disney theme parks, if there's a compelling theme park environment, a lot of the work is already done (particularly since Disney isn't really that good at storytelling in the conventional sense on theme park attractions) in making a land or attraction work. It becomes easy to create a theme park land or attraction about interacting with this environment and the unique challenges contained within it, regardless of whether or not there is a conventional narrative structure or identifiable characters for riders to follow-and, frankly, more of Disney's iconic attractions fit that mold than is commonly acknowledged, because in many instances, traditional metrics of character, plot, etc. do not actually matter or determine whether or not something is successful as a theme park attraction.
For example: how many of the ghosts of the Haunted Mansion can you actually name? Ok, now how many would you be able to name if you weren't an uber nerd-I say this with love-posting on a theme park board, and who is therefore likely really into this stuff? Is knowing their names beyond giving them a generic description, i.e. the caretaker, actually important to what happens on the ride or how riders engage with it? It's not. Does Haunted Mansion have a big, detailed plot in the conventional sense? As much as fans and Disney themselves have increasingly tried to concoct one, the answer remains Not Really. And yet the attraction works and has become a classic because of its compelling environments and the way they are presented.
The same principle is true for the world of Avatar, and that's why the franchise works as the basis of a theme park land but more beloved Marvel or Pixar films largely do not. Pandora is never going to have the merchandise sales of a Potter land, but it works as a compelling environment, while also allowing bigwig CEOs to pat themselves on the back and feel good about what they're doing because it's also technically IP. So as long as they do it appropriately (admittedly a big ask to the modern leaders), there's nothing wrong with Pandora on paper-in fact, it already works better than several more conventional hot properties that people seem more ok with them building out.
And since there's already been an incredibly successful first Avatar movie, there's now an incredibly successful sequel (with more on the way), and there's already a highly regarded existing themed area based on the franchise that works pretty well, I really don't understand why people insist on having arbitrary conversations about how much space Avatar does or does not take up in pop culture. The impact of the franchise isn't in doubt-it's already here and demonstrable.