Death of a Salesman

In Authur Miller's Death of a Salesman, Charley told Willy "the only thing you got in this world is what you can sell". That statement can be interpreted in many different ways, but I believe that Charley was not being literal: however, he meant that Willy had to sell himself, so to say. A good salesman is one who has power over people. He can convince people to buy what he is selling, and he is good at what he does.
In psychology, we learned something called "foot-in-the-door". Basically, it means that salesman wont take no for an answer. They will continuously put their foot in your door to stop you from shutting them out.
Willy doesnt have this trait anymore. Yes, he may have been a great salesman in the past. I know this because he spoke on mulitple occassions about how so many people in all different states loved him and he was very well known. But as he grew older, I believe he lost his spark. He no longer carries this trait, so therefore, he can no longer be a good salesman.
If "the only thing you got in this world is what you can sell", and you arent selling anything, then Willy isnt a good salesman.
Charley and Willy had a conversation, and Charley mentioned to him something about giving him a job, and after Willy denied, he made that statement. I think that all ties into selling yourself. Willy cant make a living if he doesnt sell himself.