“The Chief and the Pauper” is the final episode of “The Simpsons” that Keeler wrote; he then moved on to creator Matt Groening’s next series, “Futurama.” One of the first episodes of “Futurama” he wrote, “When the Aliens Attack”, contains meta comments similar to the kind in “The Principal and the Predator”.
Chunks of the episode is a simple sent “Independence Day”; Omnicronians invade Earth and destroy the landmarks. What connects this to “Pauper” is why aliens are attacking; they wanted to see the finale of “Single Lawyer,” a 20th century television show that was eliminated during its original airing. Omicron Persei 8 is 1000 light years from Earth so the Omicronians only received the series recently.
Since there are no copies of the episode available, the Planet Express crew will air their own version. Leela (as protagonist Jenny McNeal) tries to make a tough ending, abandoning the law and proposing to the judge (played by Professor Farnsworth). Fry (and the Omicronians) vetoed this ending, forcing Jenny to remain a single female lawyer. As Fry put it, “Smart things make people feel stupid, and unexpected things make them feel scared.” It’s hard not to imagine Keeler thinking about the reaction to “The Principal and the Cannibal” as he wrote this line.
“When Aliens Attack” ends with Fry recounting the essential rule of TV: “At the end of the episode, everything always returns to normal.” The scene then looks out to New York in flames from the invasion. However, certainly, things to be back to normal in the next episode. This, like the epilogue to “The Chief and the Pauper,” Keeler is warning that for TV screenwriters, the status quo is the rule.
https://www.slashfilm.com/946806/a-simpsons-writer-still-defends-this-infamous-episode/ A Simpsons Writer still defends this infamous episode