Given the poor state of the ship, and the implication that the passengers and crew have resorted to cannibalism, it is most likely that the Simpsons were the only people onboard to have survived in spite of being left to die in Antarctica because of Bart's mistake. Either the ship struck an iceberg and sunk with no survivors (because of isolation), food ran out and everyone starved after eating each other, or they just snapped from insanity and killed themselves?
How is it that none of the cruise passengers, or even the cruise staff, recognized the movie clip of the general warning everyone about the pandemic? Especially if it was from a movie that the cruise provided for practically everyone in their cabins?
