Not inherently flawed, but the longer most stay on, the less interesting or more aggravating and boring they get. It's why I can't stand later seasons of
Family Guy, Simpsons, South Park, and
Rick & Morty especially. They either rely too much on pop culture, spinning the same characters over and over again without them growing/resetting them, or just go extra on hard on the edge lord/"fart sniffing nihilism" shit, and think that's all they need to be "smart and witty". I tend to not bother with most animated comedies from the West, because they're either just copying
SP or
R&M whole sale (thankfully, the few
R&M clones pretty much died off fast, or went into their own direction), or way past their prime. Say what you will about
Smiling Friends, but at least the creator of the show did not want it milked and did not want another case of character developing for the worst or have character derailment and bullshit retconning.
Before anyone brings up
Archer, it suffered similar problems later in the show's life. Every time the show changed its name, the quality dropped, and certain characters like Lana can fuck off. I know I stopped caring when the first name changed happened, and they went to Miami. It was nothing more than dumb gimmick after dumb gimmick.
I tend to gravitate towards animated action shows from the West, because they either ironically have better story telling/writing compared to most sitcoms, and don't take themselves too seriously, or know how to have fun without being overly preachy, or acting as if violence/nihilism is the only answer. Some of these shows can get dark, but they don't self-indulge, nor act as if they have all the answers.
Most of them suck especially nowadays but I think early adult swim stuff was good shows like Space Ghost, Venture Brothers, and Sea lab 2021 were great. I feel like a lot of cartoon writers are just shitty obnoxious people that want respect that they don't really deserve shows like Rick and Morty, mordern South Park and Bojack Horseman are great examples of this.
The only show that's still going that I still consistently enjoy is American Dad it's not trying to prove anything it's just entertaining.
The early adult swim days had its ups and downs, but most of the adult comedies from the start actually cared about writing more than shock/gore humor, or learned to lean into the absurdness and weird. Though this got worse, and started to become problem post
Robot Chicken.