In the era of media overload it's obviously pretty hard to get people to even get interested in anything, so it's common to have an interesting punchline to draw people's attention. Here are some stuff I loosely follow that started off with an interesting punchline, but was quickly abandoned:
Kaguya - Love is War
You know how there's always these guys with 300 IQ coming up with some crazy plan that is actually pretty dumb but it works because the guy came up with the plan has 300 IQ? Well, Kaguya - Love is War, you got those same plans except they almost always fail spectacularly. Kaguya is basically about a bunch of nerds who score #1 in the world in a standardized test who may have seen something on Youtube and thought they're now MacGuyver or your typical Internet superhero and then embarrassing themselves on their braindead plans. It's one of the relatively big hits in recent years and now it's totally become the typical soap opera romance manga and I don't think I've even seen any such plans executed in an year or so. Oh, and inexplicably, all these dumb plans executed by the cast that never worked now always works, because they're all supposed to be 300 IQ geniuses so of course they have calculated everything to perfection.
Dungeon Meal
Dungeon Meal is about a group of adventures that wiped on the dragon boss and ended up with one of their member more than usually dead (the other guys got resurrected at a save point earlier). The leader of the group decided that their failure was because they spent too much money on food so now they'll learn to be like cannibals and eat whatever monster they slay for food instead. However, the story never told you what they did with the money they saved by eating monsters instead of food. I mean the whole point of the story allegedly is that if they saved the money on food for gear instead they could've beaten the dungeon, but this part is literally never addressed. I haven't really followed it in a long time, but I think they even stopped eating monsters for food and now it's just some typical high fantasy dungeon crawler.
The Legendary Hero Is Dead Because He Fell In My Trap
As the title implies, the main character is a farmer that digs up traps to try to trap wild boars or something, and one day the legendary hero visited his village and fell into his spike trap and died so now the main character has to go save the world. For maybe first 30 or so chapters the main character relied on digging various traps to defeat demons, but as of right now he's managed to train himself to be stronger than the legendary hero due to his fetish for legs or something. It's not even really good fan service and I think people overwhelmingly prefer the the guy who always fights naked, or the Mr. Satan/King character who fights while riding an invincible horse (but everyone thinks the horse is his power).
Now I know there are some things that seems to start off with a gag that actually has a long term plan. For example Helck seems to be about a gag about the legendary hero and joining up with demons to exterminate all humans, but if you're even remotely paying attention you'd have noticed that Helck didn't join the demons to kill all humans just for the lolz so there was always a clear building toward finding out why he decided to do that. These series seems to be purely started off as a gag and meant to be a short-lived thing since they all started on barely known serialization (Kaguya actually got moved to a bigger serialization because it was funny), so after some initial success they're trying to apparently pivot to some totally generic high fantasy/romance or whatever the genre they're in. But good high fantasy or action stuff is dime a dozen, and most of these attempts to pivot aren't even good. I understand they may run out of gags but maybe that's a sign you should stop. Sure there's always money involved but unless you're like Bleach where you already made enough money even after being blacklisted from every major serialization for dragging on way too long, it's probably good to leave in a positive standing with the publisher/fans so you can do something else later.
Kaguya - Love is War
You know how there's always these guys with 300 IQ coming up with some crazy plan that is actually pretty dumb but it works because the guy came up with the plan has 300 IQ? Well, Kaguya - Love is War, you got those same plans except they almost always fail spectacularly. Kaguya is basically about a bunch of nerds who score #1 in the world in a standardized test who may have seen something on Youtube and thought they're now MacGuyver or your typical Internet superhero and then embarrassing themselves on their braindead plans. It's one of the relatively big hits in recent years and now it's totally become the typical soap opera romance manga and I don't think I've even seen any such plans executed in an year or so. Oh, and inexplicably, all these dumb plans executed by the cast that never worked now always works, because they're all supposed to be 300 IQ geniuses so of course they have calculated everything to perfection.
Dungeon Meal
Dungeon Meal is about a group of adventures that wiped on the dragon boss and ended up with one of their member more than usually dead (the other guys got resurrected at a save point earlier). The leader of the group decided that their failure was because they spent too much money on food so now they'll learn to be like cannibals and eat whatever monster they slay for food instead. However, the story never told you what they did with the money they saved by eating monsters instead of food. I mean the whole point of the story allegedly is that if they saved the money on food for gear instead they could've beaten the dungeon, but this part is literally never addressed. I haven't really followed it in a long time, but I think they even stopped eating monsters for food and now it's just some typical high fantasy dungeon crawler.
The Legendary Hero Is Dead Because He Fell In My Trap
As the title implies, the main character is a farmer that digs up traps to try to trap wild boars or something, and one day the legendary hero visited his village and fell into his spike trap and died so now the main character has to go save the world. For maybe first 30 or so chapters the main character relied on digging various traps to defeat demons, but as of right now he's managed to train himself to be stronger than the legendary hero due to his fetish for legs or something. It's not even really good fan service and I think people overwhelmingly prefer the the guy who always fights naked, or the Mr. Satan/King character who fights while riding an invincible horse (but everyone thinks the horse is his power).
Now I know there are some things that seems to start off with a gag that actually has a long term plan. For example Helck seems to be about a gag about the legendary hero and joining up with demons to exterminate all humans, but if you're even remotely paying attention you'd have noticed that Helck didn't join the demons to kill all humans just for the lolz so there was always a clear building toward finding out why he decided to do that. These series seems to be purely started off as a gag and meant to be a short-lived thing since they all started on barely known serialization (Kaguya actually got moved to a bigger serialization because it was funny), so after some initial success they're trying to apparently pivot to some totally generic high fantasy/romance or whatever the genre they're in. But good high fantasy or action stuff is dime a dozen, and most of these attempts to pivot aren't even good. I understand they may run out of gags but maybe that's a sign you should stop. Sure there's always money involved but unless you're like Bleach where you already made enough money even after being blacklisted from every major serialization for dragging on way too long, it's probably good to leave in a positive standing with the publisher/fans so you can do something else later.