But not all premises are created equal, and not every film has the substance to properly support an extended universe, or in this case, a film series. Especially once you get past a linear series and into the realm of the franchise, the only ideas with the potential to thrive are those that really do build worlds — concepts that go beyond individual characters or narrative arcs, that can adapt to a variety of genres and styles and narrative structures. Concepts that can evolve.

The worlds of Westeros and Middle Earth and Star Wars’ galaxy far, far away represent universes of possibility. That doesn’t guarantee that Amazon’s gamble on a $250 million Lord of the Ring series or HBO's Game of Thrones prequel pilot or future installments of the Star Wars franchise will be any good. It just means that they have potential. Ultimately, the most enjoyable films are those that live up to their potential. It’s one of the reasons why films which represent somewhat limited possibilities, like a by-the-numbers rom-com or an action flick with more explosions than brain cells, can sometimes provide a more satisfying viewing experience than other, arguably superior films that feel like they still could have been better — the former lived up to its full potential while the latter did not.

Jurassic Park had the potential to be an iconic Hollywood hit, and it lived up to that potential in 1993 under the direction of Steven Spielberg. While the four sequels released since have more or less lived up to the original in terms of box-office success, none have come anywhere close to receiving comparable critical acclaim. This issue is not a matter of diminished talent or resources or a lack of honorable intentions.

Simply put, the 1993 Jurassic Park not only lived up to its potential as a film, but also maxed out the narrative capacity of its fundamental premise. There’s nothing any sequel can possibly do to fix this, no matter how hard it may try. The central idea of Jurassic Park is that of scientists bringing dinosaurs back to life to populate an island zoo and sell a Jurassic-era tourist experience. It’s a premise that appeals to one’s inner eight-year-old, but living T. rexes are also not the smartest idea. And that’s every Jurassic Park film in a nutshell: an island full of dinosaurs is very cool, and also a bad idea. There’s nowhere else for the premise to turn. If the cool idea of an island full of dinosaurs doesn’t go bad in practice, then there’s no drama and therefore no movie, and if there’s no island full of dinosaurs then it’s not Jurassic Park.

Jurassic World: Fallen Kingdom does try to move the narrative forward by introducing the idea that dinosaurs will no longer be confined to an island, and that the genetic technology that created them is now in more hands. But in terms of narrative possibilities and potential themes, changing “island” to “world” doesn’t actually change anything at all. The fundamental issue remains the same: dinosaurs are cool and also extremely dangerous. Fallen Kingdom dares to expand a little upon the franchise’s fascination with the idea of geneticists gone wild, producing some of the film’s least redundant moments, but in doing so brushes up against an existential quandary that marks yet another limitation inherent to the franchise: if it’s Jurassic Park, it has to be about dinosaurs. Expanding “dinosaur de-extinction” to more general shenanigans (including human cloning) involving megalomaniac geneticists in a more central way would erode the distinction separating Jurassic Park films from general sci-fi.

The Jurassic Park franchise hit a bull's-eye on the first shot, but narratively speaking, it’s a gun with only one bullet. It’s done. And yes, the setups can and will be tweaked for as long as people keep buying tickets. But the punchline will always be the same. There is no room for expansion, only repetition.