At the end of the book, Violet can't talk, move, or even think. Her feed function is at a mere 4.6% (which means it's really, really bad). We would probably call this a coma. In the last scene, Titus sits by her bedside, telling her the story of herself. (Remember: as Violet's feed started to malfunction more and more toward the end of the book, she was most afraid of forgetting who she was.) And the last story he tells her is the story of the two of them:
It's about this meg normal guy, who doesn't think about anything until one wacky day, when he meets a dissident with a heart of gold [. . .] Together, the two crazy kids grow, have madcap escapades, and learn an important lesson about love. They learn to resist the feed. (58.14)
In our last view of Titus, we see him watching the image of himself crying, reflected from one of Violet's blank eyes. This is capped off with the last bit of feed chatter: huge sales going on, and how "Everything must go." And what's super depressing about this? The story he tells her is not the story of the book. They get half way there, but then one of the crazy kids dies and the other—well, he does seem to learn a lesson, but he hasn't exactly become an activist. Instead, he moves on to Quendy.
This super depressing ending hints that it may be lights-out for America. Remember, there have been several threats of bombing thrown back and forth between the United States and the Global Alliance, and many cities have erupted in riots. We get the feeling that "Everything must go" has a double meaning—like, "all of humanity."