I was laughing my ass off in almost every episode in season 11 because Dennis seemed to be at his absolute peak antisocial personality. Most of the show was coherent and flowed well. The characters were narcissistic, scratched libs and constantly concern trolling each other. Things were largely grounded in reality.
Then season 12 and up, things just got weird and tiresome to watch. Like things just happen back to back and everything is grandiose. The character development is undeserved because they cram in so much shit in 20 minutes (like the episode of Mac coming out as gay is just Frank yelling the same thing for 20 minutes then Mac dances. Come on. They had a whole season to build up to it and instead they just did this shit). It feels like I’m watching Uncut Gems but instead of being stressed out, I’m just annoyed by the wild stories and annoying characters. Like the one episode of season 16 parodies the anal vibrator chess scandal because the scheme is…?
And now the gang is soft as hell and actually getting offended as opposed to be socially conscious for their own agendas. And honestly, I think they could’ve dulled out the characters if they played it out right, like with how Dennis wanted to be a family man, that’s a valid path to make him less antisocial and misogynistic, and proceed to do this one by one for each character then ending the show.
I felt like the little commentary they had about the post-9/11 zeitgeist in the early seasons was funny and subtle at times. But it seems like the trump era really made everyone fucking annoying. Somehow they managed to fumble the plot line about the gang being responsible for the boater coup at the capitol which should’ve flowed naturally with the show.
This has always been a problem the show had. Most egregious example that stood out to me was the first appearance of Maureen Ponderosa in season 6. Dennis meets the girl he dated in high school, they get married 5 minutes later and immediately he's tired of her and wants out. The show tells us that Maureen is special to Dennis, but we have no idea why. He treats her differently than any other girl, he wants a committed relationship with her, but it doesn't tell us anything about who Maureen is or rather, who Dennis believes Maureen to be before she turns out to be an annoying weirdo. So when she does turn out to be an annoying weirdo, the joke doesn't land at all and Dennis just seems like an idiot because for all we know she's always been like that, since it's literally the first time we're told or shown anything about her.
I do agree that starting with S13, it kinda lost me. I think there's 3 reasons the show fell off:
It's been going on for like 20 years now and falling off at one point or another is inevitable. Doesn't mean the show can't get itself back together though.
The creators are different people now than they used to be. Also inevitable when you age 20 years and make a lot of money because of your hit sitcom.
I don't know if a show like It's Always Sunny still fits into the zeitgeist. People have kinda gotten softer in general, in a good way mostly. Look at shows like Brooklyn 99, copaganda yadda yadda but its characters are generally more caring towards one another than in shows that aired 20 years ago. Sitcoms have become less "mean", characters talk about their feelings more and it's not perceived as funny anymore to kick people while they're down, at least compared to the early 2000s. The early seasons of It's Always Sunny, even if you remove the slurs and transphobia, wouldn't be as well received if they came out today as they were 20 years ago because comedy has changed. Even cynical shows like Rick & Morty have their moments of sincerity where they show that the characters do care about each other. That's really difficult for a show like IASIP to adapt to, because the entire premise is that the main characters are the worst people you've ever met