From the text:
Nobody dast blame this man. You don’t understand: Willy
was a salesman. And for a salesman, there is no rock bottom
to the life. He don’t put a bolt to a nut, he don’t tell you
the law or give you medicine. He’s a man way out there in
the blue, riding on a smile and a shoeshine. And when they
start not smiling back—that’s an earthquake. And then you
get yourself a couple of spots on your hat, and you’re finished. Nobody dast blame this man. A salesman is got to
dream, boy. It comes with the territory.
Death of a Salesman