Tennesse Williams's play, "The Glass Menagerie" is an Expressionistic play, not a tragedy. As such it involves conflict with authority, heightened dialogue that reveals the suffering and spiritual awakening of its characters, and exaggerated scenes.
In "The Glass Menagerie" there are no noble characters who make tragic mistakes. Williams, instead, portrays a most ignoble character, Tom, who is too weak to change the problematic life he has in any way but to argue with his mother, dodge his job, and flee. He and his sister and mother live an illusionary existence. Amanda, the mother, resides all too often in a romanticized past in which she was a Southern belle with "gentlemen callers." The sister Laura is crippled both physically and mentally, spending her days with glass animals. When the gentleman caller, Jim, does give her some self-confidence and the spiritual awakening requisite in Expressionism. However, with Tom's abandonment, how she and her mother will survive is under question.
While a case for tragedy can be made for a modern play such as Arthur Miller's "Death of a Salesman" as Willy Loman was at one time a successful salesman, in "The Glass Menager," there seems no original greatness in any of the three characters that would allow a fall of tragic proportions.
The Glass Menagerie is a modern literary tragedy. Here's the definition of tragedy from the eNotes Guide to Literary Terms:
In literature, tragedy refers to any composition with a somber theme carried to a disastrous conclusion.
The tone of Williams' play is certainly somber, a "memory play" that captures the disintegration of the Wingfield family and the individual sufferings of Amanda, Laura, and Tom. Each of the Wingfields is trapped by circumstances. Laura is crippled, emotionally as well as physically, unable to function in the world outside the family's shabby apartment. Amanda finds herself abandoned by her husband during the Depression, lacking the education or skills to support her family. Tom lives each day with the anger and frustration of unfulfilled dreams, going to a job he detests in order to buy another week's survival for his mother and sister.
Enter Jim O'Connor, another of Amanda's schemes to find security for Laura--and by extension, for herself--and the drama descends into its "disastrous conclusion." Laura's brief moments of happiness with her engaged "gentleman caller" end for her in heartbreak and further emotional withdrawal. Tom leaves home for good after a bitter argument with his mother, and Amanda is left to manage alone without Tom, always her worst fear. The family, as troubled as it was, is broken. The tragedy is further emphasized by Tom's life after storming out of the apartment. He finds he can't escape by running away. There will never be an escape for him. No matter where in the world he travels, he forever will be tied through memory and emotion to the sister he abandoned.