The characters of Tennessee Williams's play The Glass Menagerie are victims of their own tragic flaws as characters. Considering them as failures would not describe them fairly nor correctly, because to fail at something is terminal: there is just no way to succeed whatsoever.
The Wingfields have plenty of chances to succeed if they closely analyze how their circumstances affect them as individuals, and as a family. The tragic problem that they face, however, is that they are too co-dependent on each other to find the inner strength to save themselves first in order to go and try to help someone else. Tom does this, becoming the only character who actually becomes "saved" from the portent of a gloomy future.
In Amanda Wingfield we find a woman who cannot let go of her past. That would be her character's tragic flaw. As a result of not growing out of her past she consequentially cannot embrace her present, nor welcome a future. Her enmeshing nature leads her to depend on others for support, namely her daughter Laura and her son Tom. Meanwhile, her character remains flat; she may complaint and attempt some changes on behalf of Laura, but Amanda never really changes. That is her choice, however, and a personal choice is still considered a step taken towards achieving a goal. The fact that the choice is a bad choice is what renders her a victim of her circumstances; she does things within a very limited perspective and thinking that it is for the best. That is the tragedy of it all.
Similarly, Laura's choices come out of an inability to control her extreme anxiety. She develops the anxiety out of a physical disability. Moreover, she is enabled by her mother, no matter how much Amanda denies pampering and babying Laura. The choice of keeping to herself is used as a defense mechanism to avoid pain. Her glass menagerie is her outlet to remain somewhat useful. The tragedy in Laura's life is that she too lives in the past and is too scared to move on.
Tom had a combination of guilt and fear. He did not want to repeat the actions of his father, and that froze him for a while. When he walks out of the family he knew he would probably not make his dreams come true, but leaving the cycle of co-dependence that was his home is the first step to self-discovery. However, even at the end we see that he too has taken a step too big; he still misses Laura.
Jim, as a secondary character, represents the pre World War II world; still recovering from the horrid punch of the Great Depression, and with a slight hint of hope for the future. He is not a failure, in fact, he is the most hopeful of the characters. However in his case, his tragic flaw is having tasted success as a high school beloved and then having to taste the sad reality of everyday life as an adult.
In all, they are not failures; they all really try to find happiness. However, in true Williams fashion, the tragedy must be present for the audience to truly appreciate how the struggle that the character goes through to strive and succeed can still be crushed by its trying environment.