Final answer:
Tom realizes that he must prioritize his own desires over his responsibilities towards others.
Step-by-step explanation:
In The Glass Menagerie, Tom's realization at the end of the play is that he must prioritize his own personal desires and dreams over his responsibilities towards others, specifically his family. Throughout the play, Tom feels trapped and suffocated by his responsibilities towards his mother and sister, but he eventually realizes that he cannot sacrifice his own happiness for their sake. He chooses to leave his family behind and pursue his own dreams, even though it may lead to loneliness and uncertainty.