Avengers Arena: The promises that the series would feature a lot of deaths by the end resulted in a heavily Broken Base, with some people rejecting the book out of fear it would become too dark.
Avengers vs. X-MenflanderizesCyclops into a Jerkass and derails Captain America into being one as well. While the ultimate purpose of the crossover (to undo the damage done in Decimation) is good, the way the crossover was carried out just pissed everybody off.
Cable: Tischman's brief run had a sound concept: averting the Reed Richards Is Useless trope by exploring what would happen if a godlike superhuman intervened in real (sort of) wars. Unfortunately, in execution, the cast consisted of 75% villains (including everyone on both sides of the various conflicts, even the side Cable ostensibly fights for), 21% helpless victims, 3% actually sympathetic characters who accomplish anything, and 1% Cable himself, who is a Mighty Whitey played depressingly straight and who flat-out admits that even with all his phenomenal power, he can't really change anything, and that his goal is to make things better for only a handful of people for the immediate future.
Civil War: The post-Civil War Marvel Universe often feels very oppressive. The heroes, with few-and-far-between exceptions, are written as being either well-intentioned but immensely flawed at the very best or horrible/hypocritical people with flimsy moral standards at worst. Coupled with the villains getting nastier and nastier, it only ensured nobody would care who won. Following the events of Secret Invasion, Dark Reign sees Norman Osborn being put in charge of S.H.I.E.L.D. and forming his own Avengers team. While the heroes get small victories here and there, they are still much too divided to do anything to effectively challenge Osborn, who for the most part is always one step ahead of them. It doesn't help matters that this era sees the public reach unprecedented levels of Too Dumb to Live, blindly eating up everything Osborn and the Dark Avengers want them to believe and demonizing the actual heroes. Thankfully, things began to look up with the resurrection of Captain America, though it's not until Siege that this era is finally brought to an end, reuniting the Avengers into one team.
Civil War II: The series treads similar ground as its predecessor, the only real change being that it's a debate on whether Pre Crime Arrest is a good idea or not (turns out that the future-seer Inhuman that is central to this plot not only provides very sketchy information (so a Prophecy Twist is heavily assured), but said visions are only of probable futures (Screw Destiny is a pretty heavy possibility, and acting on the visions has a high chance of them becoming a Self-Fulfilling Prophecy). This information is presented to the pro-Pre Crime Arrest faction, who doesn't gives a crap.) The whole thing has been written trying to present both sides as sympathetic... the problem is that this was done by stuffing War Machine in a fridge, and makes both Captain Marvel and Iron Man unable to stop wangsting long enough to ask themselves if what they are doing is actually being a Well-Intentioned Extremist or just trying to one-up each other, and on top of this the Inhumans have taken so many levels in jerkass that it resulted in a "Mutants vs. Inhumans" storyline. the new version of "Marvel Now" that came out of this storyline had the Marvel Universe divided once again (seriously, the Tag Line is "Divided, We Stand")... The combination of factors, including it coming up very shortly after the end of Secret Wars (2015), has had some people tossing their hands up and quitting in disgust at what seemed like a new Status Quo, where "Let's You and Him Fight" keeps happening constantly.
Deadpool: The Deadpool Kills the Marvel Universe sequel Deadpool Killustratedinvokes this sense of apathy as Dreadpool's plan. If he kills enough characters (and their inspirations), people will stop caring about the characters and whether they live or die, thus allowing him to find the oblivion he wants.
Outlawed: The event opens with the apparent death of fan-favorite Viv Vision, the hospitalization of Kamala Khan, and the passage of a new law against teenage vigilantism that's also being exploited to harass minority teenagers. The Champions are now in disarray, the New Warriors have become government stooges, which is massively out-of-character for them considering how they were victimized during the aforementioned Civil War.
Ruins: The two-issue miniseries by Warren Ellis, a Darker and Edgier take on Marvels where all of the iconic Marvel characters are either dead, horrifically mutilated, corrupt, or insane and Philip Sheldon struggles to get a book about his discoveries and encounters published before succumbing to a lethal virus. There aren't many things as depressingly dark. Made all the worse by Ellis' claim that Ruins was supposed to be a comedy.
Throughout the first three runs, the team constantly lost members or were driven from whichever hideout they were using at the time. Their few victories never lasted long, and their failures tended to have more or less permanent consequences, including death. Add in subplots about homophobia, mental illness, and depression, and the series was a hard sell.
Runaways (Rainbow Rowell) has the team reforming after two of its members are unexpectedly resurrected, but the old dynamic is not there. Nico is still haunted by the events of Avengers Arena, Gert has become so afraid of being abandoned that she is sabotaging her friends' lives so that they won't leave the team, Alex can no longer touch people without repelling them, Victor's wrestling with a Superpowered Evil Side, Molly is so lonely that she's begun to pine for her supervillain parents, and Karolina's gradually reverting to a Stepford Smiler. The only Runaway who's actually happy is Klara, and this is only because she chose to get far away from her old friends.
Secret Empire: The series has Captain America himself as an agent of HYDRA taking over S.H.I.E.L.D. and the world in just the first issue. The most powerful heroes have been cast off-world or trapped on Manhattan Island, whoever's left is on the run, kids have been indoctrinated into HYDRA sympathizers (with copious amounts of Orwellian Retcon with their books because of Cap's version of history being mucked about) and everyone was supposed to accept that everything would be set back to normal afterwards? It's no wonder fans were growling out their hatred of this story.
Peter Parker's status as a Loser Protagonist means that it unfortunately isn't rare to get a story arc that flirts with this trope. For example, Howard Mackie's run on The Amazing Spider-Man (1999) is remembered for essentially having Peter go through one Kick the Dog moment after another, from losing his job, to his wife seemingly dying, and ultimately becoming homeless. Superior Spider-Man (2013) was eventually Vindicated by History, but at the start of its original run, many fans were turned off by the decision to "kill" Peter. The more recent The Amazing Spider-Man (2022) was hit hard by this, as the run opened with Peter estranged from all of his friends and family after a Noodle Incident with Mary Jane seeing another man to boot. After sixty years of Status Quo Is God, fans are burnt out on watching Peter lose every single good thing that comes into his life (his wife, his daughter, his girlfriend, his company, his doctorate) just to end up right back where he started over and over.
Radioactive Spider-Gwen lampshades the darkness during the build-up to its "Gwenom" arc. Earth-65's designated Watcher has become completely apathetic to Gwen's plight, directly telling his fellow Watchers that her story has become too dark and angsty for him to care: she's lost her powers, her father has been imprisoned after taking the fall for her actions, and she's now forced to work for the Kingpin. Oh, and Wolverine is there. As a result, he tries to remind himself of the story's stakes by taking a break from following her storyline to focus on the more grounded problems of her bandmates. The main plot gets even bleaker once the "Gwenom" arc actually starts, so when we return to him a few issues later, he's still apathetic about it (though a fellow Watcher's horrified reactions to the events do amuse him).
Ultimate Marvel: The Ultimates 3 and Ultimatum took the Ultimate Universe past the deep end. Ultimates 3 completely abandoned the superhero deconstruction of the first two miniseries and featured instead a standard story of robot duplicates and a conflict with Magneto. And the awesome cinematic scenes of the first miniseries were replaced by shocking images taken straight from the worst moments of The Dark Age of Comic Books. And Ultimatum was a crossover event that killed off most of the Ultimate cast, usually in cruel, shocking and disgusting ways. This caused a big decline in the interest in the Ultimate comics, which never quite recovered from, even with the surging of Miles Morales and The Maker.
X-Men: A major issue with the series and all the associated mutant-related titles. Despite major progress in civil rights for racial minorities, women and LGBT+ people in Real Life during the decades since the X-Men were first introduced in 1963, in-universe the situation for mutants is consistently bleak. Indeed, given the sheer number of canonical Bad Futures that characters are either predestined to end up in, or in some cases come from, it can seem as if the humans vs. mutants conflict is a Forever War with no hope of ever getting any better. This led some long-time readers to back away from the titles.
The X-Men franchise is bleak by its very nature, given that they can never stop being feared and hated, but since 2005 the darkness was dialed up with M-Day, an event that reduced mutants from a population of millions to less than 200, with no more on the way. The remaining mutants are reduced to huddling together for protection (inside a walled compound, then inside a different walled compound, then on a tiny island) and trying to avert their own extinction. After years, the thoroughly unpopular plotline was finally resolved, new mutants start appearing again - and then Secret Wars (2015) happens. When the dust clears, the new status quo is... mutants are on the verge of extinction, no more mutants are being born, and the remaining mutants are huddled together for their own survival. Again. And the less we say about their never-ending desire to be at each other's throats for whichever reason they want to be at each other's throats, from love triangles to whoever is the Well-Intentioned Extremist-du-jour coming to blows with the ones that aren't so extreme, and the ones that are fed up with all of the crap vs. the ones that aren't, and so wish to knuckle down and keep fighting, which is occasionally the reason they aren't as effective against a threat as they should be, with the escalation reaching the point of multipleconsecutive "disbanding" arcs starting with Schism (if not earlier), the better.
