If the Iron Man series can be remembered for one thing, it’s for single-handedly kickstarting the absolute hurricane of comic book movies that has come to define our current pop culture moment. Before Iron Man, there was no Marvel Cinematic Universe. There was no copycat DC Extended Universe. Hell, the very concept of shared universes hadn’t really even gotten off the ground, for better or worse. Suffice it to say that when Iron Man premiered eight years ago in 2008, no one could have possibly anticipated its influence—and now what had been predicted to be a box office gamble, a mildly successful B-tier blockbuster at best, has the distinction of anchoring one of the most successful series in film history.

We’ll be living with Iron Man’s influence for years to come, that much is a given. But what about the curious absence of Iron Man 4? At this point, are we ever getting one? Let’s dig through the gossip and find out whether we’ll ever see one more solo adventure with Robert Downey, Jr. as the invincible Iron Man.

RDJ is too expensive

Robert Downey, Jr.’s value to the Marvel Cinematic Universe simply can’t be overstated; for years, he’s been the charismatic center of the Avengers initiative, taking the first movie, the first face-to-face with Nick Fury, and the first trilogy. This storytelling value, however, comes with a high real-world monetary price tag. As Tony Stark, RDJ hasn’t just been one of the most valuable players in the Marvel stable, he’s become one of the most valuable actors in the entire world. While nobody outside the negotiations can be precisely sure of the dollar amount Downey’s netting these days, one thing’s for certain—it isn’t small. Even modest estimates have his earning capacity at hundreds of millions of dollars, with nearly half-a-billion dollars in earnings not outside the realm of possibility. And it’s not as though these numbers ever go down. It would be no surprise if the cost-benefit analysis of an Iron Man 4, from Marvel’s side, shows less and less of a reward. And that’s fine! The end of RDJ’s involvement would by no means spell the end for a big-screen Iron Man. Like it or not, his version—beloved as it is—is more likely the beginning of something that will last awhile, rather than a role that ends with his departure.

The comic storylines are more exciting

In the comics, it’s not surprising to see an occasional dramatic passing of the mantle, wherein one hero steps into the shoes of another. Commissioner Gordon has been Batman; Doctor Octopus has been the Superior Spider-Man; Bucky Barnes and Sam Wilson, the Winter Soldier and Falcon, have both been Captain America. These departures do tend to curve back toward a status quo or reset, with the “original” version of a hero rarely being permanently sidelined. But that doesn’t invalidate the other narratives starring different heroes, and the Iron Man comics are currently going through an exciting stretch: Tony Stark is no longer Iron Man. In his place, a 15-year-old girl genius named Riri Williams has assumed the mantle—and so has Doctor Doom, in his own Infamous Iron Man title. It’s about the biggest 180-degree-turn one could imagine, and fertile ground for storytelling possibilities. You think you wouldn’t be curious to see some of these changes unfold on the big screen?

We’ve got other heroes to get to

If you’re a fan of the Marvel Cinematic Universe, you’ve likely heard about their peculiar strategy of releasing movies in “phases.” Phase 1 was the original “Avengers assemble” arc, introducing our main heroes. Phase 2, leading up to Age of Ultron, broadened the world, taking us into space and folding new heroes like Scott Lang’s Ant-Man and Janet Van Dyne’s Wasp into the mix. Now we’re at the start of Phase 3, set to introduce a slew of new heroes (and likely send a few off by the end). Phase 3 is set to culminate with the long-awaited fight with Thanos, teased for what feels like 40 or 50 years now, in 2018’s Avengers: Infinity War. Meanwhile, Captain America has already had his third adventure, and Thor will also see his third movie before Phase 4 begins. The plan appears to be a gradual handoff, as older heroes are phased out and newer ones are introduced. It’s hard to see how another Robert Downey Jr. Iron Man can fit into the mix—or the overall strategy of new heroes in, old heroes out.

Iron Man has taken on the Nick Fury role

When the MCU started, the movies weren’t as interconnected, easing audiences into the “shared universe” concept with hints and references rather than a truly serialized story. In those pre-Avengers days, the real connecting tissue was Samuel L. Jackson’s Nick Fury and the organization S.H.I.E.L.D. After a few movies spent thoroughly dismantling and destroying that institution—Hail Hydra, and all that—Nick Fury is lately nowhere to be seen, and the strongest connection between all of the movies has become Tony Stark. It’s Stark, after all, who propels the events of Captain America: Civil War, in which he basically shares top billing. It’s Stark who pulls Spider-Man into the fold, and he’ll be appearing in the web-slinger’s upcoming solo outing, acting presumably as a sort of mentor to Peter Parker (and maybe a sorta something else to single lady Aunt May, if you know what we’re saying). In short, we don’t need a fourth Iron Man movie to see Iron Man anymore. He’s already popping up everywhere else.

We’re running out of villains

Villains have admittedly never been the strong point of the otherwise very entertaining MCU. They’re all fairly one-note, and their surface-level diversity fails to cover for the fact that all of their master plans boil down to using some unearthly power to blow up buildings for 20 minutes before getting their asses handed to them by the Avengers (or the Guardians of the Galaxy, or Black Panther, Ant-Man, Moondragon, Warlock, Pip the Troll, the Nova Corps, Beta Ray Bill… whatever). No one’s seeing these movies for the villains—or, as Will Smith’s Deadshot so aptly put it in this summer’s DCEU entry Suicide Squad, the swirling rings of trash in the sky that threaten all-so-frequently to destroy humanity.

It wouldn’t be prudent for a potential Iron Man 4 to come out swinging with a villain that impresses less than the previous three, and honestly, we’re sort of running out of interesting villains that are Iron Man-specific. Now, in our opinion, there are still interesting directions they can go with this, but with Marvel’s past unwillingness to feature a female villain, particularly in the Iron Man series, it seems unfortunately unlikely. The thinking may well be that more valuable Iron Man villains, like the Green Goblin, would be better off showing up elsewhere in the universe, like Spider-Man’s neck of the woods, where he’s much more commonly known.

Oh, the rest of the cast is expensive, too

Lest we put all of the blame for running up the budget on Robert Downey, Jr.’s popularity alone, we should remember that he’s not the only superstar in his cast. Gwyneth Paltrow and Don Cheadle are in these movies, too, and they likely take home more money the more they appear as well. Add in a villain played by an actor with some star power, and it’d probably be a lot cheaper to try and make a profit on a Squirrel Girl movie than an overstuffed Iron Man sequel.

Tony Stark is running out of interesting storylines

One of Iron Man’s most famous storylines seems unlikely, at this point, to ever make it to the big screen, for better or for worse. The odds of family-friendly fun-time Disney being cool with a movie where Tony Stark confronts one of his most famous foes—alcohol—seem minimal at this point. If the character were going this direction, we would have probably seen it by now; it would be somewhat jarring for Tony Stark to start hitting the bottle after this many appearances. It’s ground that was fairly well covered, in euphemistic terms, by other movies in the series, with PTSD being the major concern of Iron Man 3. At this point, Marvel is in a bad position, story-wise. They can’t use Tony’s most famous story, but is it a good idea to go more obscure? Especially for a fourth movie. Could it be they’d rather not push their luck?

An unnecessary risk

The Iron Man trilogy is, in critics’ eyes, a three-for-three success story, despite some dispute about the merits of Iron Man 2. (Hey, we liked it.) This is hard to do! Ask the Spider-Man, X-Men, and Batman franchises how well their third installments went, for instance. Or look at series like Fantastic Four and The Amazing Spider-Man that were put to rest before getting a chance at a third at-bat. There’s a certain level of accomplishment to pulling off a trilogy that succeeds critically—not even The Godfather could do it!—and executives may well be hesitant to risk even making a fourth Iron Man movie. In short, they stand to lose more than they stand to gain. What if it’s lousy? What if it’s tired? Wouldn’t it be easier to call it a day? Especially since…

Iron Man 3 was a perfect ending

We’re getting more into the realm of opinion here, but it’s really hard to argue with the conclusion of Iron Man 3, which even at the time felt like a pretty final statement on the character. Scripted and directed by the celebrated writer-director Shane Black, the up-to-now final chapter of the Iron Man series had a lot of fun analyzing the meaning of the series and the character, playing around with a lot of metatextual concepts about what Iron Man meant. Pepper Potts wears the suit twice in the movie (which was super-fun and true to the comics), and the climax, an insane action sequence in which Stark summons something like 50 sentient uninhabited Iron Man suits to save him from an unstable, explosive villain, seems impossible to top.

It was a movie where Tony was separated from his suit for a long stretch; the movie made us analyze Tony Stark and Iron Man as separate entities, before ultimately reconciling them in the end. “My armor was never a distraction or a hobby,” says Tony, as he drives into the sunset before the credits roll. “It was a cocoon—and now I’m a changed man. You can take away my house, all my tricks and toys, but one thing you can’t take away—I am Iron Man.” It’s just a fantastic way to end the series, and to risk spoiling it with a fourth installment means flirting with diminishing the whole series. Sometimes the only way to win is not to play, and with all of these other superheroes on the shelf, maybe the smartest move is to let the series lie. We don’t need Iron Man 4, not really. The next best thing is right around the corner.

Why we never got to see Iron Man 4