South Park is one of my favorite shows of all time, although it has been slowly on the decline. 
Sorry to hear that.  It seems like a show focused on the same four boys who never grow any would start to falter.
It has been around for a long time, 1999 I want to say? I guess all things must end eventually.
That it does.  The theme song of the show could be All Things Must Pass, a song by George Harrison.
Hmmm, not sure if I've heard that song, but it's like the Simpsons, it too has been on the decline.
That's definitely another one, though I feel like the dysfunctional family aspect could make it able to bounce back.
I feel like every show has its limits, only so many things you can do with the same characters.
Yeah, they should really shift the focus to be more heavily on the recurring characters more often.
I think so too, South Park does have a lot of those. They try to introduce new ones every season.
They must have a lot, since they've been going since 1997.  It's not too amazing it's been going so long, since it had some very high ratings.