True, but it rings true more for audiences if you watch buildings crash into each other while a plane just scrapes through, rather than Kang and Kodos arguing in the middle of it all.
Well, it's always destined for an American audience so they have to have a happy ending. Perhaps if they set it oop North, where things are expected to be depressing, then just as the final strike comes to destroy the Earth, the last man alive would declare, "Aye, 'appen!" and up it goes!