It’s like nobody cared enough to bother finishing anything about this. It just kind of stops, e.g. “Note: Poochie died on his way back to his home planet.”
All grownups are doomed eventually to question whether different choices in their lives would have brought them greater happiness and comfort. Teenagers are doomed to believe that it’s possible to make choices that could avoid that fate. “The Last Picture Show” is about learning these two things.