Other.
When initial storyline is finished, but the franchise keeps going, often start and stopping attempted "second arcs," once they realize that they aren't hitting as big. This is a thinly veiled criticism of the same shit in television shows, anime, and movies, but totally applies to this hobby as well.
Recent examples: FFVII reeeeeing.
Kingdom Hearts, a series so confident in it's new direction post-Xehanort Saga to immediately start the new storyline with a game that has Xehanort as a final Boss, directly followed by a game about his origin story.
Metal Gear. This is like gaming's Dragon Ball. Was supposed to finish at the Frieza Arc and have the entire story wrapped with a neat bow but goddamn employers and fans, so I'm gonna stretch it's corpse out. MGS2 was a thought provoking, meta narrative that played with player expectation but knew when to reel it in. It was almost prophetic in some ways, and should definitely be held up as a preserved title. Snake Eater came next, and it was short, punchy, poignant. Wasn't necessary to the story, but it didn't step on any toes.
Come MGS4, Kojima is just so fucking over it. "You were never supposed to know the Patriots identities, you idiots. This is like an autistic child refusing to eat dinner because you never find out what happened to Tom fucking Bombadil after the Ring was destroyed in Middle Earth. Fuck it, guys, Sigint was a Patriot. Para Medic, too. Big Boss, he hated the Patriots. Fuck it, he was a Patriot, too,"
By MGSV, dude couldn't even be arsed to direct cutscenes so it was just one brilliant gameplay sequence to the next bridged by tape recordings of DA VOH KULL CORRD PARASITES.
Resident Evil. Fuck, we really shot our load blowing up the fucking setting in 1999. How about we rip off that Dagon B-horror movie and put it in a Spanish place. Maybe Africa? Okay, so hear me out: The Family is an Illuminati group and the new big bad. Until the next game, now it's The Agency. Or The Unit. Or The Shield or some shit. Actually, it's the BSAA. Oh, the BSAA are the good guys. Well, uh...fuck it, that was a different branch. The main one has Zombies and shit in it.
Just LEAVE IT ALONE if it's logically finished. I give Naughty Dog mad respect for going this long without shitting out Uncharted 5-12.