Why does Biff come home in Death of a Salesman?

Biff initially poses his return home as a choice to leave the ranch out west where he has not been "getting ahead", saying:

"I'm thirty-four years old, I oughta be makin' my future."

Biff tells Happy that he enjoys working outdoors and enjoys life on a ranch, but in the many jobs he has held since leaving home he has never become a man in his own view. He describes himself as being "like a boy" and feels that he needs to find a way to establish himself as an adult in the world.

As the play goes on and Biff's tendency to steal is revealed, the audience reasonably wonders if Biff has moved around from job to job so much because he has been fired and/or caught stealing.  

Biff, who steals things as an adult, blames his father for not giving him the proper guidance when he was caught stealing as a child.

Many of Biff's disappointments appear to be marked by theft, as is his failed visit to his former boss, Oliver, in the sporting goods store.