Why is the play called "Death of a Salesman"?

On the literal level, it is, indeed, about the death of the salesman, Willy Loman. However, more importantly, it is a tragedy concerning the death of the American Dream that Willy Loman represents. Willy Loman realizes that as a salesman, he doesn't "put a bolt to a nut,he don't tell you the law or give you medicine" (Requiem); a salesman just sells, with nothing to show for his efforts, except, at the highest level, money, a materialistic reward that can be gone in a moment. Willy spends his life working for material goods, and at the end of the play, after his suicide to provide the family with money, his wife only has a house that is paid for. Linda says, "We're free and clear," yet her husband is dead. Thus, the American Dream, to have more things is actually the death of what once defined America, the strength of the American spirit. Willy Loman represents us all-those who become entrapped by the wrong dream and sacrifice life. This point is illustrated best by Willy's garden - his attempt to actually grow something, yet his house is surrounded by a "solid vault of apartment houses." Obviously, Miller uses strong imagery in the opening scene description illustrating Willy Loman's prison.