Why do all the characters become as awful as their parents? : Franzen's Freedom

Joey told his dad, Walter, that he's in a lot of trouble and now, piece by piece, we're completing the picture of his trouble - all of his own doing. He's a selfish, nasty, self-centered kid who's had everything handed to him and screws it all up. Again, he keeps within the pattern of the book, which is reaction formation - he does all in his power to be different from his parents and becomes equally horrible in a different way. That pattern I can understand. I can't quite understand the drift that goes on within generations. Patty & Walter Bergland seemed like a perfectly "nice" couple who broke free of terrible childhoods, found each other, found some meaning in life and family. And what happened? Why do they, over the course of the novel, become as awful as their own parents, though in a different way - drinking, fighting, cheating? Walter at least seems to have some political values - although he betrays his values given the opportunity - working for a nature conservancy controlled by a pillaging coal magnate. Compelling as I find Jonathan Franzen's "Freedom," I'm disturbed by the darkness of his view of humanity, by the little shop of horrors that forms the gallery of his characters. It's beyond satire - I don't think satire is hi milieu - it's just a grim expose of how people behave, or misbehave. The book is losing is moral anchor, as Patty, the "nice" daughter/wife/mother, goes down the tubes. I am about 2/3 of the way through and hoping that the characters, at least one character?, will learn something and mature and show a sign of maturity and hope.