I think that one way in which Miller's work embodies a modern tragedy is that it consists of "regular" people. Willy has an "Everyman" quality about him. He is not a king, or ruler of ancient lands. He is a "regular guy." He finds himself placed in the situation of measuring up to an impossible standard. Willy is not cursed by the gods or by anything other than the situation in which he lives. It is for this reason that Willy's characterization was so entirely understood by audiences that watched the drama:
[Audience members] were weeping because the central matrix of this play is ... what most people are up against in their lives.... they were seeing themselves, not because Willy is a salesman, but the situation in which he stood and to which he was reacting, and which was reacting against him, was probably the central situation of contemporary civilization. It is that we are struggling with forces that are far greater than we can handle, with no equipment to make anything mean anything.
In this respect, the drama is a modern tragedy because of its applicability and way in which Willy is every person. Modern tragedy is universal in its application and Willy is certainly applicable to anyone and everyone who dreams.
At the same time, the drama is modern in scope because it seeks to free itself from the need to provide a harmonizing ending. In ancient drama, the purpose of the drama was to provide a morality play in which a harmonious ending in which greater truths are understood by both characters and the audience is evident. Miller's drama is more realistic in scope, seeking to not bring about totalizing endings at the cost of depicting reality. Miller is able to present and depict a realistic state of being in which there are more questions than answers. This lack of totality is another aspect that helps to make the drama a modern tragedy. The construction of modern tragedy as one in which its use is a "more flexible term, often simply referring to a story where some of the characters’ lives or story arcs end badly" can be seen in Miller's drama.