Chris Hemsworth, Robert Downey Jr., Chris Evans, Scarlett Johansson, and Chris Pratt are some of the hottest stars in Hollywood right now, and this fact raises an interesting question (aside from “Why are so many of them called Chris?“) These actors are, along with a growing collection of others, the faces of the phenomenally successful Marvel Cinematic Universe. But does the MCU owe its success to the star power of these actors, or do they owe their current Hollywood pedigree to the MCU?

Star power – that is to say, the perceived financial value of having a certain actor attached to a project in a leading role – has long been a powerful but fluid entity in Hollywood. Actors jump up and down the roughly-hewn hierarchy of hotness that starts with the highly coveted “A-list” category at the top and goes all the way down to the more humble names on the “C-list” and “D-list”, who might turn heads in a restaurant but leave people struggling to remember their name.

The original cornerstone of the MCU was Iron Man, released in 2008 with the irrepressibly charismatic Robert Downey Jr. playing Tony Stark. Iron Man grossed just over $585 million worldwide. When Iron Man 3 was released five years later, it grossed more than double that amount. In those five years, Iron Man‘s blend of action, wit and adventure had come to define the MCU, and Downey Jr.’s role was deemed so valuable that when various superheroes came together for The Avengers, his earnings were greater than that of the rest of the main cast members combined.

Of course, even Marvel movies that feature no Iron Man at all have proven to be big box office hits. Between Thor and Thor: The Dark World, Chris Hemsworth has led Asgard’s favorite son to rake in over $1 billion at the box office. And yet we’re now coming out of a year that has been bookended by two Hemsworth-led failures: Michael Mann’s hacker thriller Blackhat, and Ron Howard’s historical whale-hunting action drama In the Heart of the Sea. Blackhat, which had a budget of $70 million, squeaked into theaters in January and left having grossed less than $20 million worldwide. Meanwhile Deadline reports that In the Heart of the Sea looks as doomed as its poor sailors.

Mann and Hemsworth took to the Hall H stage at San Diego Comic-Con 2014 to present Blackhat, perhaps to try and draw in the superhero-loving crowd to a more serious film by way of its star, and also to capitalize on the fact that Hemsworth was already present at the convention for Marvel Studios’ Hall H presentation. Sitting in the audience, however, the response to the Blackhat trailer felt distinctly muted. The audience was excited to see Thor on stage, but not to see Hemsworth out of his armor and red cape, trying to track down cyber-criminals.

Chris Hemsworth and Michael Mann filming Blackhat What the Marvel Cinematic Universe Tells Us About Star Power

Chris Hemsworth and Michael Mann filming Blackhat

Hemsworth’s current plight isn’t unique; many of Marvel’s hottest stars are hot specifically because of their ties to the Marvel brand. Even Marvel’s golden boy and the highest-paid Avenger can’t really lay claim to any recent big successes when he wasn’t wearing a metal suit. Downey Jr.’s last truly successful feature outside of the MCU was 2011’s Sherlock Holmes: A Game of Shadows, which made money but doesn’t look like it’s about to get a sequel any time soon. Last year he reunited with Iron Man director/co-star Jon Favreau (and Avengers co-star Johansson) for comedy-drama Chef, which was well-received but fairly low-key, and played the lead in courtroom drama and transparent Oscar bait The Judge, which flopped at the box office and only managed one Academy Award nomination… for Downey Jr.’s co-star, Robert Duvall.

Evans, who has expressed a desire to get out of the acting game and into directing, can also thank Marvel for his biggest acting success story. He played the lead in Bong Joon-Ho’s dystopian sci-fi movie Snowpiercer, which was loved by critics but barely broke even at the box office, in part due to some dismal mishandling by U.S. distributor The Weinstein Company. As for Evans’ directorial debut – a romantic comedy called Before We Go, in which he also played the lead – the best that can be said about it is that it was slightly better received than Evans’ next foray outside of the MCU, another romantic comedy called Playing It Cool.

In defense of these three actors, their Marvel commitments leave them with limited time for other projects. Each of them have at least two standalone movies under their belt as well as two Avengers movies, and playing lead roles in these blockbusters means months of filming, followed by reshoots and then press tours. With that said, Johansson has also played Black Widow four times, and managed to prove her star value in Luc Besson’s hit sci-fi action film Lucy.

Avengers 2 Age of Ultron HD Still Bruce Banner Black widow What the Marvel Cinematic Universe Tells Us About Star Power

Star power comes into play most of all for original movies or new adaptations, when a recognizable name is needed in order to attract funding, and for franchises like Mission: Impossible and Terminator, where the brand has becomes synonymous with a particular lead actor. In the case of the MCU, the Marvel brand itself has become its own genre-defining hook. Its for this reason that, in 2014, Guardians of the Galaxy was led by an actor best known for his supporting role in a sitcom, another actor whose most successful previous movie saw her playing an entirely CGI character, and a man better known as a wrestler rather than an actor. Guardians‘ most “A-list” stars were relegated to providing the voices for a raccoon and a tree.

While it would be nice to think that Marvel’s success has been a game-changer, the studio’s habit of putting little-known directors at the helm of massive blockbuster movies and turning “B-list” and “C-list” actors into “A-list” stars may simply highlight the reality that so-called “star power” is more embedded in the psychology of Hollywood than in hard evidence of its influence at the box office. Earlier this year we looked at the question of whether there’s a formula for box office success, and one of the impressions we came away with was that some Hollywood rules are based more on superstition than actual evidence of trends.

This may well hold true for the idea of movie stars as well. While it might be comforting for a studio executive to believe that the right actor can make any movie a success, the fact remains that Jennifer Lawrence can go from leading one hugely successful franchise and playing a key ensemble role in another, to starring in a box office disaster like Serena, and then jump right back to another Hunger Games triumph. There are no guarantees. Just because fans love an actor in a particular role, it doesn’t automatically follow they’ll turn up to see them in another. All the Loki fan blogs in the world couldn’t save Tom Hiddleston-led gothic horror Crimson Peak from its fate.

Comic Con 2013 Chris Hemsworth and Mark Ruffalo signing autographs What the Marvel Cinematic Universe Tells Us About Star Power

The topic of star power has attracted a lot of interest from researchers over the years. Harvard Business School‘s Anna Elberse used online simulation game Hollywood Stock Exchange to measure the value that people attach to particular actors. She notes that an actor’s “star power” isn’t based on the financial success of previous movies alone: “They may have critically acclaimed acting skills, possess personality traits that appeal to the movie-going audience, attract a lot of free publicity, have the ability to secure investment, or simply have been lucky.” Based on data garnered from HSX, Alberse estimates that “on average, stars are worth about $3 million in theatrical revenues.”

Arthur De Vany and W. David Walls’ 1999 paper “Uncertainty in the Movie Industry: Does Star Power Reduce the Terror of the Box Office?” is far less generous towards the theory of star power than Elberse’s, concluding that the belief in particular actors having a certain amount of box office value attached to their name is simply another Hollywood superstition – a comforting security blanket against the ever-looming boogeyman of box office failure. “Movies are complex products,” the authors point out. “The cascade of information among film-goers during the course of a film’s run can evolve along so many paths that it is impossible to attribute the success of a movie to individual causal factors.”

For Marvel’s part, the studio seems to put more stock in smart casting than in actors’ existing laurels. It’s now difficult to imagine anyone other than Downey Jr., for example, as the cocky, fast-talking Tony Stark. Pratt embodies the perfect combination of good looks and comedy chops to play the swaggering, over-confident outer-space outlaw Star-Lord. Evans is the embodiment of the clean-cut, all-American, idealistic superhero. Johansson easily steps into the role of a hard-bitten femme fatale with a vulnerable side. The focus seems to be less on finding actors who were perfect in other roles, and more on finding actors who will be perfect for Marvel roles.

Guardians of the Galaxy Star Lord Drax What the Marvel Cinematic Universe Tells Us About Star Power

One of the things that makes this so exciting for fans of the MCU is the fact that the next big superhero could be almost anyone. Yes, Benedict Cumberbatch might have been an obvious choice to play Doctor Strange, but that’s merely evidence of the fact that Cumberbatch was practically born to play a well-bred, high-cheekboned surgeon/sorcerer (we may have to eat our words if Cumberbatch ends up being a really terrible Stephen Strange). And if Hemsworth can make the leap from being an Australian soap star to playing the God of Thunder, then who knows who might end up playing Captain Marvel.

It might be hard to imagine a Mission: Impossible movie that does not have Tom Cruise performing some kind of insane stunt, the MCU is no longer defined by one particular star. While Downey Jr. may have been the original Avenger (in movie chronology, not in-universe chronology), there have been plenty of Marvel movies that were successful without the presence of Iron Man. Since the Marvel brand itself – and the aesthetic, tone and narrative approach shared by the Marvel movies – has become the MCU’s greatest strength, the studio is in a strong position to simply hire the best actor for the role, regardless of what they’ve done before.

Of course, the real test will come when (and if) Marvel has to transfer the mantle of an established superhero to a new actor. Can a Captain America movie succeed without Chris Evans? Is the identity of Iron Man irrevocably tied to the persona of Robert Downey Jr.? What if Marvel Studios took a page from the recent comics and had a female character take up the hammer of Thor? If nothing else, Spider-Man will be good practice for that eventuality.

Captain America: Civil War will be release on May 6, 2016, followed by Doctor Strange – November 4, 2016; Guardians of the Galaxy 2 – May 5, 2017; Spider-Man – July 28, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; The Avengers: Infinity War Part 1 – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.