Why does Willy tell Howard about Dave Singleman in Death of a Salesman?
Let us remember that at this stage in the interview Willy senses that things are going badly for him and he is fighting for his job. As he tries to engage a "barely interested" Howard in what he is saying, he reveals his own inspiration and role model for becoming a salesman, who was Dave Singleman. Note what he tells Howard about this legendary figure (to Willy at least):
And he was eighty-four years old, and he'd drummed merchandise in thirty-one states. And old Dave, he'd go up to his room 'understand, put on his green velvet slippers--I'll never forget--and pick up his phone and call the buyers, and without ever leaving his room, at the age of eighty-four, he made his living. And when I saw that, I realised that selling was the greatest career a man could want.
Of course, it is Dave Singleman who gives the play its title, as it was his death that brought "hundreds of salesman and buyers" to his funeral and made things "sad on a lotta trains for months after that." Dave Singleman thus represents the personal side of sales, which is in direct contrast to the impersonal reality of sales that Willy is confronting now. In his own words to Howard, it is "all cut and dried" and there is no room for "friendship." Of course, the massive irony of Dave Singleman is that Willy's "death of a salesman" is completely different to Dave's. Willy dies unremembered, apart from his family, and represents a victim of the capitalist system rather than a hero.