How to prove that Willy Loman was a bad salesman? "Death of a Salesman"?

Question

I'm trying to prove that Willy Loman was a bad salesman, I've got a few points down but can't seem to make enough out of it.

Thanks!

Answer 1

What about extra "service" to the clients? It's unprofessional.

Answer 2

Willy was not so much as a bad salesman, but someone out of touch with reality, who was old fashioned and did not adapt. He held on to a false dream, one that could not be realized, because of his moral failures, and because that was his tragic flaw. He was old and tired and out of touch, but he would not admit that he was never going to reach his goal which was to be like old Dave Singleton and die in his robe and slippers on the train between calls and have cars from all over the region at his funeral. Poor Willy.