Of course, any show that's on for so long is bound to experience some drift, but The Simpsons really doesn't fit into any of these categories. And the more I htink about it, the more it seems like they're really theater of the absurd. Case in point:
In "The Bob Next Door" (sn 21, ep 22) we start with a town council meeting about budget problems, complete with a montage of minor criminals who are being set free because the govt can't afford to kee them locked up anymore. (Case in point, a man who tries to eat Apu's fruit without paying for it.) These and other cost-cutting measures lead to the Simpsons' neighbors decamping - in Lisa's words, "Another Springfielder moves to Detroit in search of a better life." Homer, lured by the scent of fresh cookies, attempts to buy a house nextdooro. At the last minute he's outbid by a Walt Warren, and we're treated to a scene of the girls watching Mr. Warren unpack, speculating about his furniture and koi fish.
All of which is a lead-up to the fact that Warren is, in fact, Sideshow Bob. Simpson afficionados can probably guess what inevitably follows.
This is all so random, but hilarious as well. As is the "five corners" motifs (I spotted both TX and NJ accents among the cops...) I don't know why, but somehow it never gets old.