The Brothers Judd website has a good point...
“Miller, in reducing capitalism to nothing more than a kind of cheap hucksterism, has followed in the footsteps of Theodore Dreiser, Sinclair Lewis, F. Scott Fitzgerald, and the like, with equally obtuse results.
It is the genius of capitalism that chaff like the Willy Loman’s are ruthlessly winnowed. Willy and his sons are so transparently phony it makes your flesh crawl just listening to them. It’s not as if Willy had been steadily advancing through the business world and then suddenly hit the wall. He’s spent forty years on the lowest rung of the corporate ladder for a reason. That reason?, he has been judged inadequate, long before his age caught up to him. This is a man who should have been a gym teacher and an athletics coach. But not only has he deluded himself and ignored forty years of messages from the system, he also insists that his sons follow in his clearly misguided footsteps.”
And F. Scott Fitzgerald may be the worst “left wing” writer in the world even if you could categorize him as such. He tried his hand at it in the 1930s because he was being hounded by Hollywood leftists and communists (the awful wife of Nathaniel West comes to mind) and he was desperate for money to help clear up his debts and provide for his wife. Possibly America's greatest writers, I'm surprised you would single him out.
P.S.: the other writers you mention are pretty damned good too.