I've seen the episode, it was titled "The Simpsons Already Did It", but if you will recall, at the end of the episode, the other cast members informed Butters that TV shows borrowing ideas from other programs has been going on for decades, even before The Simpsons, and also that even The Simpsons itself has been guilty of doing so, so your analogy really doesn't work here.
The point is: it's not about being 100% original, becasue it's been established that this is next to impossible. Sometimes it's not the idea, but what you do with it that makes it one's own.