The Titular Salesman

I recently read Arthur Miller's Death of a Salesman.  By the end of the play, I couldn't really figure out who the salesman in the title was.  While it might seem more obvious that the salesman in Willy Loman, I would actually argue that the titular salesman is Biff.  The rest of this post contains spoilers.

Near the beginning of the play, we learn that Biff has been out west doing mostly odd jobs and things that don't at all resemble the more business-attuned job that his father has.  Through Willy's memories of the past, we can see Biff's ambition, at least part of which has the aim to impress his father.  While Biff is trying to get something going with Bill Oliver, Willy ends up losing his job.  Later, they have an argument about Biff's failure to get any business started, after which Willy crashes the car and dies.  The play ends with his funeral.

Since Willy is the character who dies and is the only main character in the play who is a salesman, it would seem that he is the title character.  And while that can be true, Biff could also be the title character.  Where Willy the salesman dies after working for decades, Biff the salesman dies before he can even get started.  In the argument that Willy and Biff have shortly before Willy's death, Biff says, "I am not a leader of men, Willy, and neither are you.  You were never anything but a hard-working drummer who landed in the ash can like all the rest of them!  I'm one dollar an hour, Willy!  I tried seven states and couldn't raise it.  A buck an hour!  Do you gather my meaning?  I'm not bringing home any prizes any more, and you're going to stop waiting for me to bring them home!"  Biff doesn't die, but his ambition does.