The House of Mirth Book 2 Chapters 11-12

In the 11th and 12th chapters of Edith Wharton's The House of Mirth, Lily has been fired from her job. I find it sad, but slightly humorous, that Lily gets fired from a job, for before, she was much to good for a job, yet now, she isn't good enough. Lily's getting fired just makes her story even sadder. This sets in on Lily, and she decides she will go blackmail Bertha Dorset. I thought for a moment, that the story may have a happy ending for Lily, but, alas, she decides she will go to Selden instead. It seems as if her life will not get on track. When she is with Selden, she burns the letters. She is now doomed to her meager existence. I still don't understand why Wharton couldn't have had Lily and Selden get married, having Lily get over her need for wealth that way. It doesn't seem the story needed to come to this, but truly it has. I would have much rather seen Lily and Selden together, for they were seemingly the perfect couple. Rather than the happy ending that could have been, it seems we are in store for a sad ending. While Lily was preoccupied with the material things in life, and wasn't the greatest of people, it doesn't seem fitting for her to end like this, poor, and fired from a job at a hat store. Wharton writes "What debt did she owe to a social order which had condemned and banished her without trial" (Wharton 244)?  Lily hadn't been given a fair chance to prove her innocence, but neither did she try to. Lily truly seems to be doomed to a poor lonely life.