How does Arthur Miler deal with the themes of success & frustration in Death of a Salesman?

Tied up intimately with the idea of the American dream is the concept of opportunity and success, the American dream. America claims to be the land of opportunity, of social mobility. Even the poorest man should be able to move upward in life through his own hard work. Miller complicates this idea of opportunity by linking it to time, and illustrating that new opportunity (or success) does not occur over and over again. Bernard has made the most of his opportunities; by studying hard in school, he has risen through the ranks of his profession and is now preparing to argue a case in front of the Supreme Court. Biff, on the other hand, while technically given the same opportunities as Bernard, has ruined his prospects by a decision that he made at the age of eighteen. There seems to be no going back for Biff, after he made the fatal decision not to finish high school. Willy is an example of chasing the illusion of success. Hard work and talent escape Willy. All he is left with is the frustration of the broken pieces of his illusion of the American Dream.