Here’s how the universe came to be, according to the best information available: About 13.7 billion years ago an infinitely dense, ultra-hot singularity began expanding. It’s kept expanding, and has evolved into everything everywhere. Here’s how you create a cinematic universe, according to the best information available: Make movies focused on vibrant, charismatic characters while establishing that they share a world. Make it clear that they’re all participating in a mega-narrative that spans all the films set in that world. Create a sense of investment by making those connections stronger as the films start to pile up. Keep evolving and expanding. Create a big bang that’s propelled by the laws of physics to only keep getting bigger.

That’s the model followed by the Marvel Cinematic Universe, a 19-film (and growing) series that began with 2008’s Iron Man and seems destined to go on forever. In an era of box office uncertainty — when theaters have found themselves competing with everything from Peak TV to video games to not having to deal with other moviegoers by staying home — they’ve been reliable moneymakers. And as moviegoing has come to focus increasingly on oversized blockbuster entertainment, they’ve given audiences the closest to sure things they’re likely to find. “Audiences know what they are getting when they see an MCU movie,” Jason Guerrasio, senior entertainment reporter at Business Insider, says. “Lots of action, strong characters, and, likely, an appearance from a familiar face in the MCU. As long as they don’t deviate too much from the formula, the movies are going to have box office success.” The best Marvel movies are very good. The worst, well, they’re not that bad either.

Marvel has been pretty transparent about its master plan, laying out distinct phases of films and often announcing several projects at once and letting fans theorize about how they’ll fit together. In interviews, Marvel Studios president Kevin Feige remains tight-lipped about upcoming plot twists but seems happy to talk about Marvel’s overall strategy and creative ambitions. The blueprint has been public information for a long time. Why is Marvel’s the only skyscraper in the skyline?

In the wake of Solo: A Star Wars Story’s underwhelming box office performance -- which will certainly not have lasting harm to Star Wars as a franchise but establishes its current approach to universe-building as far from flawless -- it’s a good time to ask why others have had such trouble following Marvel’s example. Why have so many would-be cinematic universes collapsed in on themselves, or failed to burst into existence in the first place?

Below are a few possible explanations, but first a qualification. There is another successful shared cinematic universe out there: Fox’s X-Men films. The series has had its ups and downs, seeming to bottom out in the mid-aughts with the unsatisfying X-Men: The Last Stand and the disastrous X-Men Origins: Wolverine. But it’s since rebounded via well-liked entries in the series proper and X-Men-adjacent films like Logan and Deadpool. It operates like a modestly scaled, more erratically scheduled version of the Marvel Cinematic Universe, one blissfully unconcerned with maintaining a consistent tone or serving a larger narrative. But though the first X-Men films predate Marvel Studios’ movies, they’re so closely tied to the MCU by a common source — Marvel Comics — that they tend to get overshadowed.

The X-Men universe operates as a kind of eccentric cousin to the MCU’s superhero movies, which is fitting given that’s more or less the role played by the mutants in Marvel’s comics. Whether it will continue to play that role now that Fox — which maintained rights to the mutant characters thanks to deals made before the beginning of the MCU, and is possibly in the process of being acquired by Marvel’s corporate parents at Disney — remains an open question. Its continued success remains an outlier in an MCU-dominated field. But why?

The Movies Are Bad

To criticize Warner Bros.’ recent films based on DC Comics characters is to court the wrath of a loud, tireless corner of the internet, but consider this: When the MCU began, Marvel Studios mostly had B-list characters at their disposal. The MCU kicked off with Iron Man at a time when Tony Stark was hardly a household name. Neither were Thor and Captain America, to say nothing of characters whose fame hardly extended beyond the comic pages like Black Widow, Hawkeye, and the Guardians of the Galaxy. In creating what’s come to be known as the DC Extended Universe, Warner Bros. had Batman and Superman, characters kids learn to recognize at roughly the same time as their parents’ faces.

For some reason, Warner Bros. hired Zack Snyder to direct Man of Steel, which took Superman in a bold, new, super-depressing direction with no sense of what made the character remarkable. They doubled down with the nihilistic Batman v. Superman: Dawn of Justice. Both look like coherent artistic statements next to the nearly avant-garde incoherence of David Ayer’s Suicide Squad. These films were designed to usher in a cinematic universe to rival the MCU, with the optimistically titled, Snyder-directed Justice League Part One set to introduce a slew of new characters who would then appear in films of their own.

Things didn’t go according to plan. Snyder had to leave Justice League, which had already lost “Part One” from its title, for personal reasons a few months before its November 2017 release. The tepidly received film that made it to theaters bore the stamp of a troubled production, with Snyder’s scenes stitched together with banter-heavy sequences rewritten and reshot by Joss Whedon, who’d previously played a major role in the MCU. While the upcoming months will see a Justice League spinoff featuring Aquaman and a DCEU film starring Zachary Levi as Shazam, it would be tough to describe the DCEU as being on the right track, mostly because (vocal few aside), nobody much cares for the movies. That DC is committed to making these characters interact only deepens the problem.

The sole bright spot has been Patty Jenkins’s terrific, and beloved, Wonder Woman, and it’s probably no coincidence that it has the least connection to the grimness that dominates the rest of the DCEU — and that it focuses on a genuinely heroic character who seems motivated by a need to help people. It also seems to be a model for some of the DC projects at various stages of development: Hire a director with a clear vision for the character and let them see it through. Hence Matt Reeves’s upcoming Batman movie, which may or may not connect to the DCEU and may or may not star Ben Affleck, a possible Todd Phillips Joker movie with no plans to include Jared Leto, and so on. All of which suggests Warner Bros. might want to deemphasize the extended universe part of the DCEU. Which brings us to another possibility …

Not Everything Should Be a Cinematic Universe

I can remember the long, seemingly permanent hiatus between Return of the Jedi in 1983 and the special edition rereleases in 1997. People were so hungry for anything Star Wars that we even grudgingly tolerated Han not shooting first and the addition of a full-on musical number featuring a song called “Jedi Rocks.” Later, the three-year gaps between each prequel were just long enough for forgetfulness to creep in, and with it a desperate sense of hope. There was never too much Star Wars. In fact, there was never enough — or so we thought.

In the Disney-owned, post–George Lucas era, Lucasfilm’s strategy seems to be one of saturation, making sure there’s always something out there for fans to consume. Upcoming projects include the still-untitled Episode IX but also a new trilogy to be directed by The Last Jedi’s Rian Johnson, another series of films overseen by the Game of Thrones team of David Benioff and D.B. Weiss, and a Boba Fett movie directed by James Mangold — and those are just the projects that have been announced. (Also in the works: a live-action series for Disney’s over-the-top digital service.)

Will it be too much for all but the most dedicated fans? Maybe. Post-Solo it’s worth considering whether Star Wars works better as an occasional event, whether making too many visits to that galaxy far, far, away has a demystifying effect. Where Marvel rolling out a new chapter in its ongoing story every few months feels right, and true to the material’s comic book roots, Star Wars may not work the same way.

On the other hand, maybe the problem is Solo. “I personally don’t think it shows people are sick of cinematic universes,” ScreenCrush editor Matt Singer says. “More that they’re sick of prequels and that this one, in particular, didn’t interest people. People don’t love Han Solo; they love Harrison Ford.” Which raises another possibility: Maybe Star Wars isn’t building a strong enough cinematic universe. “Solo didn’t really connect to the other movies the way The Avengers connects to Civil War,” Singer continues. “It was very much a classic prequel that explained stuff people didn’t want to know in the first place. It didn’t build off past movies; it drafted off past movies.” In other words, a cinematic universe is only as strong as its weakest entry, and without a strong connection to an ongoing story, Solo looked optional. Many opted out.

The Plans Take Precedence Over the Movies

On May 22, 2017, Universal announced the name for its long-gestating series of films featuring classic monsters: The Dark Universe. The press release also included the revelation that a remake of Bride of Frankenstein would be the next film in the series after the soon-to-arrive The Mummy, and featured a photo of Mummy stars Russell Crowe, Tom Cruise, and Sofia Boutella next to future Dark Universe headliners Johnny Depp and Javier Bardem. Eighteen days later, The Mummy arrived in theaters. Shortly after the Dark Universe started to collapse. Universal pulled Bride of Frankenstein from its schedule, and though preproduction on the Bill Condon–directed film has resumed, the future of the overarching project looks pretty shaky.

The plan should have been foolproof. Universal essentially invented the idea of a cinematic universe in the 1940s when it discovered that teaming up its iconic monsters created new interest in the characters. (Another Dracula movie? No thanks. A movie in which Dracula meets Frankenstein’s monster and the Wolf Man? Now we’re talking!) The architecture for the modern universe looked pretty solid, too, with Crowe’s Dr. Jekyll set to serve as a kind of Nick Fury figure connecting the stories together.

The only problem: The first and, to date, only Dark Universe entry, The Mummy, suggested that more energy had been expended planning the Dark Universe than filling it. Directed by Alex Kurtzman, The Mummy is the sort of film that happens when nobody is sure what audiences want so the filmmakers throw in a bit of everything. It’s got jokes, action set pieces, Tom Cruise grinning, spiders, and an ocean of CGI effects. What it doesn’t have is a compelling story or a memorable monster, which seem like prerequisites for a studio wanting to get into the compelling-stories-with-memorable-monsters business.

That’s been a common problem for would-be cinematic universes. Studios think long at the expense of thinking short. King Arthur: The Legend of the Sword withheld familiar Arthurian characters like Merlin and Lancelot, saving them for planned sequels that will likely never arrive. But in the effort to make a lot of movies about King Arthur and his Round Table, Warner Bros. tripped at the first step: producing a kick-off movie that would make audiences want more. (At least King Arthur managed to get one movie to the screen. A pitch for a Robin Hood cinematic universe purchased by Sony never even got that far.) Is it a matter of audiences sniffing out the calculation? That might make sense if Marvel didn’t make its calculation part of its marketing plan. It’s just hard to get repeat customers when the first taste doesn’t satisfy, no matter how insistent the promise of more and better movies to come.

If at first you don’t succeed, try, try again. We’ll see tests of this approach in the near future as Paramount rethinks its Transformers franchise via a Bumblebee-focused film directed by Laika Studios head Travis Knight, due later this year, and Warner Bros. ties its hopes to giant monsters via a 2019 Godzilla film, which is intended to introduce new antagonists and lead into Godzilla vs. Kong, scheduled for 2020.

Still, it seems unlikely that we’ll see a project find success on the scale of the MCU in the near future. Justice League essentially served as a referendum about whether the DCEU would be able to rival the MCU. (It didn’t pass.) What happened with Solo will likely lead to some soul-searching about overexpansion and protecting the Star Wars mystique, if not a change of plans. And maybe asking whether or not we’ll ever see another successful shared cinematic universe again isn’t the right question anyway. Maybe we should be asking what comes next, what’s on the other side of the MCU, whether Hollywood will find other ways to lure moviegoers away from all those others distractions, and whether there might be alternatives to a box office strategy tied so closely to big-budget franchise movies whose failure could have devastating consequences.

Here’s how the universe will end, according to the best information available: We have no available information. It could expand forever. It could suffer heat death. It could collapse on itself. Here’s how shared cinematic universes end: We don’t know that either.

An earlier version of this piece mistakenly stated that Han shot first.

Keith Phipps is a writer and editor specializing in film and TV. Formerly: Uproxx, The Dissolve, and The A.V. Club.