why do you think willy tries to tell howard about dave singleman

Dave Singleman represents why Willy became a saleman and exemplifies the way in which his profession has changed. Willy wants Howard to understand that when he started it was all about "personality," and the opportunity to establish professional relationships. Howard's actions are proof of his point, as Willy subsequently loses his job. Efficiency has replaced relationships and actions are "all cut and dried."

Willy goes to Howard's office hoping for a non-traveling sales job (per the request of his wife), but Howard tells him that no job is available. He is almost ignoring Willy, and even refers to this middle-aged man as a "kid," illustrating that he does not respect him. Willy keeps lowering his salary request and tells Howard of Dave Singleman because he was a salesman that never left his hotel room. He is seen as very good at his job and well-respected because many people attended his funeral. The story does nothing to help Willy's plight because Howard essentially fires Willy at the end of the conversation. That's what he means when he says to drop of the materials. Willy pleads with Howard, but he does not change his mind and Willy leaves feeling like a failure.