Nah. The Simpsons just has problems making interesting episodes, but I wouldn't call them bad, just boring

Now SpongeBob and Fairy Odd Parents……that's a different beast.

Eh honestly South Park's one of the few shows I can think of that hasn't really lost much steam despite how long it's been going on for. Granted I know some disagree with that, but that's just how I personally feel.

I will grant this much, with South Park focusing so heavily on current events each season, inevitably some of the jokes will become outdated in some fashion. Like the episode where the kids are all obsessed with Guitar Hero. That episode is basically one big time capsule to that time in the mid to late 00s when Guitar Hero and Rock Band were all the rage. Also the "Go God Go" two parter had Cartman hotly anticipating the release of the original Wii console, and even earlier I remember an episode from either 1999 or 2000 having Cartman gushing about getting a Dreamcast.