Why did the Arrowverse and the Marvel Cinematic Universe succeed, when other shared universes failed? Marvel Studios made history in 2008, when they launched the Marvel Cinematic Universe. Hollywood was initially skeptical, but over the years, the idea of an expansive shared universe proved to be a successful one. By the time The Avengers grossed over $1.5 billion worldwide in 2012, every other studio was desperately attempting to jump on the shared universe bandwagon. And yet, for all that's the case, the only other real success story in terms of a shared universe is on the small screen. DCTV launched the Arrow TV series in 2012, and to everybody's surprise, it soon served as a launchpad for numerous other superhero shows.

In a quirk of timing, both the MCU and the Arrowverse are essentially about to be relaunched. The first three phases of the MCU are now known as the "Infinity Saga," building up to a climax in last year's Avengers: Endgame, which served as the swan song for Robert Downey Jr.'s Tony Stark and Chris Evans' Captain America. The Arrowverse, meanwhile, finally built up to the much-anticipated Crisis on Infinite Earths — a story it had been teasing since The Flash season 1 premiere — and rebooted the Multiverse. All this was achieved at the cost of Stephen Amell's Oliver Queen, meaning the Arrowverse too has lost its foundational hero. The coincidence of timing is ironic, to say the least.

Related: The Arrowverse Can't Properly Use Batman Anymore

All this means now is the perfect time to take a look back at the history of the MCU and the Arrowverse and ask a simple question: Why did these two shared universes succeed, when so many others have failed?

Why So Many Shared Universes Have Failed

DCEU MonsterVerse and Dark Universe

The last decade has seen pretty much every studio attempt (and fail) to launch multiple shared universes. Universal's Dark Universe was DOA after The Mummy bombed, the first stage of the DCEU was chaos incarnate, and even King of the Monsters failed to reap a comfortable profit. Even Will Smith planned to launch a cinematic universe bigger than the MCU, but After Earth was panned by critics. And, meanwhile, countless frankly insane ideas never really got off the ground at all; Sony's Robin Hood cinematic universe was probably the dumbest of the lot.

Ironically, the core problem is that studios have usually been a little too eager to build these shared universes. The Marvel Cinematic Universe took its time, establishing each individual character before finally bringing them all together in 2012's The Avengers; Marvel aimed to make each individual movie as good as they could, with the shared universe adding context rather than dictating the plot. In the same way, Arrow had been running for two seasons before the first spinoff, The Flash, was launched. As vast as these universes may have now become, they started out slowly and developed organically. Few studios have been willing to take the same approach with their own shared universes, with execs instead desperate to make bank as quickly as possible, and so unwittingly sabotaging their own efforts.

Related: The Real Reasons For Marvel's 2015 Split

Looking at the failures, one also gets a sense that there is no overarching vision for the various franchises. The MCU has had its own stumbles, but it has become ever more successful due in large part to the increasing dominance of Kevin Feige, while the Arrowverse has been guided by mastermind Greg Berlanti. In contrast, other cinematic universes usually find creative visions compromised by competing interests, as studio execs intervene in order to course-correct the films while they're in production — the result of that conflict was most plainly seen in the DCEU's Justice League.

Arrowverse & MCU Both Succeeded By Doing The Same Thing

There are striking similarities between the MCU and the Arrowverse, and one of the most surprising is the fact they both faced the same problem early on: neither Marvel nor DC technically had access to their biggest brands. Marvel had to launch the MCU without Spider-Man and the X-Men, while Warner Bros. restricted the Arrowverse from using characters they planned to appear in the movies. Ironically, in both cases this actually helped. The lack of guaranteed hits meant producers, directors and writers focused on making each movie and each episode as strong as it could possibly be. Both franchises saw some inspired casting choices, with Robert Downey Jr. defining Tony Stark and Chris Evans embodying Captain America, while Stephen Amell delighted fans as Oliver Queen and Grant Gustin is still seen as the definitive Barry Allen.

It's no coincidence both the Arrowverse and the MCU are comic book adaptations. These films and TV shows are essentially repeating what the comics have been doing since the 1950s and 1960s, smashing together different heroes in versus matches and team-ups. These comics can be viewed as proofs of concept, helping to figure out what works and what doesn't. They include epic stories — like Jim Starlin's Infinity Gauntlet and Marv Wolfman's Crisis on Infinite Earths — that can be adapted when the time is right. In contrast, many of the other shared universes feel artificial, existing only as potential money-making devices.

Oddly enough, both the MCU and the Arrowverse made early mistakes. The MCU's Phase 2 suffered from behind-the-scenes conflict, as Marvel Studios imposed the Infinity Stones plot on their writers and directors; creators found themselves chafing under the controversial Marvel Creative Committee, and by 2015, things had become so bad Disney forced a corporate restructure. The Arrowverse's problems were less pronounced, but they're still visible in the lackluster Arrow seasons 3 and 4, with Arrow's showrunners struggling to make their street-level vigilante work well in an expanding world of superheroes. But, in both cases, the issues were ultimately resolved and creators found a new balance.

How Both Franchises Can Continue Without Their Main Heroes

MCU Phase 4 2020

It will be fascinating to see what the future has in store for the MCU and the Arrowverse. As noted, in a quirk of timing, both franchises are relaunching themselves at the same time, and it's too soon to say whether they will maintain their momentum — especially given film and TV alike has been disrupted by the coronavirus pandemic. The post-Avengers: Endgame relaunch is transforming the MCU into a transmedia cinematic universe, expanding on to the small screen through Disney+ limited series like WandaVisionMs. Marvel, and Falcon & Winter Soldier. Some successor franchises have already been set up: Avengers: Endgame featured a scene featuring Black Panther, Spider-Man, and Captain Marvel that clearly signposted their importance to the MCU's future. And, meanwhile, Marvel aims to continue launching at least one new franchise each calendar year.

Related: Marvel’s New Phase 4 Slate: Every MCU Movie Release Date (2020-2022)

The Arrowverse, however, is in a slightly less stable position. On the one hand, the loss of Stephen Amell shouldn't affect it too much; Arrow may have laid the foundation, but for years The Flash has been the most popular show, and Grant Gustin and his supporting cast are still on board. What's more, the Arrowverse is now gaining some new big-name brands, with a Superman & Lois series set to launch next year. But there are still problems, mostly involving casting. Ruby Rose left Batwoman after just one season, and the show is set to introduce an original character as her successor, something of a gamble. As well, The Flash lost Hartley Sawyer's Ralph Dibny after some tasteless social media posts surfaced online. Up until now, the Arrowverse has had a reputation for top-rate casting, but that has been soured somewhat of late.

Still, there's no reason to assume the MCU's Kevin Feige and the Arrowverse's Greg Berlanti can't overcome the obstacles they face. These two visionaries have successfully navigated choppy waters, learning crucial lessons about how to make shared universes work, and they're sure to continue to flourish. Ironically, they'll do so in a field that's now emptying of competition, as other studios and networks gradually figure out shared universes aren't quite so easy as they look.

More: Every Arrowverse Actor Who Plays Multiple Characters (& Why)