Your question presumes that each of the characters in The Glass Menagerie, by Tennessee Williams, is a failure, which is a big assumption. Though it is true that this is not a particularly hopeful play and none of the characters ends up exactly where they wanted to be in life, the characters do not have to be considered failures.
Amanda Wingfield has many goals in life which she does not realize. She wants to have a happy family, but her husband has left them (her), her son is miserable, and her daughter is afraid of nearly everything. Despite these things, Amanda does achieve one success, though it does not happen as she planned. She is concerned that Laura is always going to be alone, so she asks Tom to set Laura up with someone from work. The young man is already engaged, of course, so there is no wedding in Laura's future; however, because of this failed "date" with Jim O'Connor, Laura finally seems to be able to break out of her insulated world. (More details on that in the paragraph about Laura.) The two women, by the end of the play, are better equipped to face whatever is ahead of them.
Tom Wingfield is desperately unhappy living at home (with his annoying mother) and working at a job he hates; more than anything he wants to join the merchant marines and travel the world. Despite his unhappiness, Tom supports his family until he can stand it no longer and leaves. He does join the merchant marines and he does travel the world. At the end of the play, Tom says:
I left Saint Louis. I descended the step of this fire-escape for a last time and followed, from then on, in my father's footsteps, attempting to find in motion what was lost in space - I travelled around a great deal. The cities swept about me like dead leaves, leaves that were brightly coloured but tom away from the branches.
It is true that he is still not content, always "driven by something." Nevertheless, he did make his dream come true and should not be considered a failure.
Laura Wingfield is like her menagerie, fragile and not quite of this world. She is unable to complete her typing course because she gets too nervous under pressure, and she is the perpetual peacekeeper between her nagging mother and surly brother. She lives on dreams of the past and seems to have no view toward the future (which her mother has plenty of on her behalf). When she finally spends a rather odd evening with the boy she had a crush on high school, everything changes for Laura. When they dance, Laura's "impediment" is no longer crippling to her. When Jim inadvertently breaks the horn off her precious glass unicorn, it is symbolic of Laura's becoming a "real" woman rather than the ethereal dreamer she had been. Though we do not know Laura's fate after the play ends, we do realize that she is better equipped to live a more normal and fulfilling life. The "spell" has been broken, and to that extent she is not a failure.
After being rather a wonder in high school, Jim O' Connor had high hopes for his life. While he has not yet achieved everything he hoped, he has not given up and is pursuing things which could one day help him realize his dreams. He is not a failure, either.
Perhaps it would be fair to say that all of these characters suffer from unrealized goals and unfulfilled dreams; however, that does not necessarily make them failures.