One possible approach to reading and understanding this play is to regard it not as a personal tragedy resulting from the failings of one individual, but as a lament to a society that is structured to bring such individuals to ruin. Some argue that Miller intended this play to expose the corrupting influence of American society and how materialism and the myth of the American dream was responsible for the tragedy of so many. If you take this view, then Willy is cast in the role of helpless victim as he is prey to wider and bigger societal forces that exert their influence on him.
It appears that Miller uses the tragedy of this ordinary man (note Willy's last name, Loman, which seems to point toward his status as a "low man") to make serious comments about the state of American society. The most significant challenge that Willy presents against such a society that is consumed by materialism is the inevitable conclusion that he comes to: he decides that twenty thousand dollars is worth more than his life. And yet, the play asks, can a man really only be valued at the amount of money he is worth? The warning is clear - if American society has been successful in giving humans a monetary value, then they have also reduced human beings to nothing more than commodities, leading to dehumanisation and the objectification of humanity.