Marvel has proven to be fertile ground for the Marvel Cinematic Universe, as the publisher has under its belt some of the greatest comics ever published. The MCU has taken advantage of this, adapting many fan-favorite stories over the years, even if sometimes they kind of dropped the ball. However, the MCU has gone in a lot of interesting directions, ones that have diverged from the comic Marvel Universe.
This has made adapting some stories impossible —sometimes it's impossible to put them on the big screen in any recognizable form. Beyond that, there are some stories that just wouldn't gel with the MCU for a variety of reasons, be it their story developments or just the overall quality.
10 The Falcon & The Winter Soldier Has Guaranteed No Bucky Cap Stories Will Ever Be Adapted
The MCU is on its second Captain America, as the former Falcon has taken up the shield. In the comics, there have been several versions of the Star-Spangled Avenger, including Bucky himself taking the mantle after Captain America was "killed" (but really pulled into a null time bubble where the Red Skull tortured him). Bucky was Cap for several years before Steve Rogers returned and there were some great stories during that period.
With Steve giving Sam his blessing at the end of Endgame and him proving himself in TFATWS, any reason for Bucky to become Cap has been taken away, meaning years of stories are off the table for adaptation.
9 WandaVision & The Lack Of X-Men Precludes House Of M From Happening
In the comics, Scarlet Witch had plenty of breaking bad moments and House Of M is the most memorable. However, with the way things are looking in the MCU, there's pretty much no reason to adapt this story at all. In fact, it's doubtful it will ever happen in the future.
WandaVision is probably the closest the MCU will ever get to Wanda being evil —she's one of the most recognizable heroes left and they aren't going to make her as bad as she's been in the comics. On top of that, House Of M breaks mutants completely and the MCU won't want to do that any time soon.
8 The Lack Of Asgard Invalidates Any Reason For Siege
Siege served as the end of the Dark Reign storyline. While there have been indications that the MCU is going to go in the direction of the Dark Avengers, it's doubtful MCU fans will ever get Siege on the big screen. For one thing, the MCU is hero-centric, so putting villains in charge just isn't going to happen. For another, there's no Norman Osborn or Asgard.
While Siege would be a lot of fun, it's just not exactly the kind of story that the MCU is going to do. It's too dark, there are too many integral factors missing, and it would take years to build up to.
7 No Tony Stark Means No Classic Iron Man Stories Like "Demon In The Bottle," "DoomQuest," or "The Mask In The Iron Man"
Tony Stark's death in Endgame was a huge deal, as he was the MCU's inaugural hero and most popular member. While there's a chance the mantle will be passed down, without Tony in the armor, a lot of classic Iron Man stories are never getting adapted.
No Tony means no "Demon In The Bottle." "DoomQuest," featuring Tony vs Doom in Arthurian times, and "The Mask In The Iron Man," when the armor becomes sentient and goes after Tony because he doesn't love it, are adaptable but lose most of the impact without Tony in the suit. The loss of Tony Stark closes off a lot of great stories.
6 Too Many Avengers Have Been Taken Off The Table For "Avengers World" To Work
"Avengers World" was superstar writer Jonathan Hickman's first Avengers story and it was a doozy. Featuring the largest, most diverse roster of Avengers ever, it pitted them against Ex Nihilo and his sister Abyss. It's an amazing story but there are just too many factors missing to make it work.
Hickman packed the team with superheroes from across the Marvel Universe and while some of them exist in the MCU, most of them aren't around anymore. While it might be possible to make the story work without them, it would defeat the purpose of the roster and beyond it, it's doubtful the MCU would go in the direction the story took things.
5 Avengers Forever Is Too Complicated & Not Really Needed
Avengers Forever is an amazing tale that every Avengers fan should read, but that doesn't mean it's going to get adapted. The book combines Avengers from the team's past, present, and future to defend against a threat that wants to erase humanity from time and also serves to clean up decades of tangled Avengers continuity.
While the MCU has played with time travel stories, Avengers Forever would be a little much for it. Beyond that, the MCU Avengers don't need the continuity clean-up the story made possible and is all around just too complicated for the more casual fans of the MCU to enjoy.
4 Thanos In The MCU Doesn't Win Enough To Make "Thanos Wins" Work
"Thanos Wins" is one of the best Thanos stories not written by Thanos creator Jim Starlin. It sees Thanos dragged to the end of time by the Cosmic Ghost Rider to meet his future self, who has killed just about everyone in the universe. It's a great story but it will never be adapted.
For one thing, Thanos is too dead for it to work. This isn't insurmountable but an even bigger factor is the fact that Thanos doesn't win in the MCU. His win-loss record is at one and one, and he isn't exactly inevitable. He can't even kill a hero without the Infinity Gauntlet. All of this works against the story getting adapted.
3 The Inhumans Are Too Tainted For Inhumans Vs X-Men To Ever Happen
The Inhumans were Marvel's great mid-2010s experiment and it was a complete failure, both in the comics and beyond. The Inhumans just weren't likable, no matter how Marvel tried to make them into the heroes of any story they were in. Inhumans Vs X-Men was a perfect example of this as the X-Men were fighting for their survival, while the Inhumans were fighting to keep genocide going and they were somehow the good guys.
Marvel has already failed with the Inhumans and they aren't going to try again any time soon. On top of that, they want to build the X-Men up, seeing as how they just got them back. For those reasons, this story will never happen.
2 Everything Is Against Civil War II Ever Happening
Civil War II pitted Iron Man against Captain Marvel in a wannabe Minority Report plot involving a future-seeing Inhuman. It will never be adapted and not merely because it's one of the worst events of the 2010s. There's just too much against it ever happening.
For example, it makes Captain Marvel the villain, not something the MCU is going to do. It needs Tony Stark to work and he's gone. An Inhuman is integral to it and they're persona non grata in the MCU. The irony of it not getting adapted is that the only reason it was ever made was to cash in on Captain America: Civil War.
1 Secret Empire Will Never Happen No Matter What
Secret Empire had so much potential but it all got squandered. Its metaphor was especially prescient at the time but a lot of fans were unhappy with the direction it took Captain America in the build-up, and the subsequent series was bloated.
To begin with, without Steve Rogers, there's no way for the story to work. Beyond that, the MCU just isn't going to make Captain America a member of Hydra. Writer Nick Spencer was trying to make a statement about the rise of fascism in the US with the story and the MCU is just too apolitical to center-right to do that sort of thing.