(I was responding to a post by SarahJ in the regular io9 about how much The Simpsons has changed over time, and then I got to thinking... and I may have stumbled across a multiverse-shattering revelation!)
I was watching the new episode on Sunday night, which was pretty sucky, and one of the things that bummed me out was the realization that the writers don't have a lot of faith in worldbuilding any more. It used to be that on the old show, there'd be all these fictional movie stars, TV celebrities, teen idols, etc. but now they tend to rely on real-life figures and institutions instead.
For example, one of the plots in Sunday's episode was that Homer used to own some Apple stock, but he sold it all back in 2001 so he could afford a fancy bowling ball. The story is pretty lame to begin with: Why would Homer own Apple, or any other stock at all? (He's not a savvy investor, seeing as how he once invested his savings in pumpkins after Halloween.) And it's also derivative and self-cannibalizing, since Homer already wasted a bunch of money on a bowling ball all the way back in Season One, in "Life in the Fast Lane."*
But here's the thing: Up until now, there hasn't been an "Apple Inc." in the Simpsonsverse. There's Mapple, the hugely successful maker of MyPhones and MyPods, founded by Steve Mobs. And Mapple is basically indistinguishable from Apple in a lot of respects, almost to the point of there not being much of a joke. (Face it, the show hasn't been great at satire in a long, long time.) And in fact, the "Apple" products shown in the episode have the Mapple logo on them, with two big, Homer-sized bites instead of just the one. So presumably, when the episode was originally written and sent to the animators, Homer sold Mapple stock instead of the real, Cupertino version. But the writers and producers decided at the last minute that the audience wouldn't get the joke, so it got changed. (And to add on-the-nose insult to injury, we then get an explanation of how enormously popular and ubiquitous "Apple" products have become, presumably for the benefit of viewers who haven't been out of the house in ten years.)
So basically, the writers no longer believe in Springfield as a special, self-contained universe with its own reality. It's just like in the movie, where "President Schwarzenegger" is basically Rainier Wolfcastle with a dye job. Granted, that made sense in a way, since moviegoers might not remember that there was a recurring character on the show who was a Schwarzenegger parody. But you can see it starting to seep into the TV version as well.
*Maybe the Simpsons' reality has rebooted, kind of like comic book universes do after a few years. Just as the DC Universe split into Earth-1 and Earth-2 in the '60s, with the original WWII era characters living in one universe, and the modernized, Cold War versions in another, "Golden Age" Simpsons continuity ended around 1999, and the show branched off into parallel realities in which the characters were Gen-X'ers, and not Baby Boomers. This is supported by the "grunge" episode that showed Homer and Marge as an unmarried, childless couple in the early '90s; perhaps the bowling ball incident on Sunday's show was from a parallel, or "Ultimate" version of "Fast Lane." And perhaps this is building up to some sort of "Crisis on Infinite Springfields," which only the cast of Futurama can resolve.