is this asking how they are different or what MAKES them different?
I think there are elements of both your ideas. Death of a Salesman came out around 1949. America was done with WW2 and heading into an age of mass consumption and conformity. THe American Dream seemed almost tangible to the middle class bent on achieving it. Two perfect kids (ideally one of each gender) a perfect home with a perfect domestic mother waiting for her husband to return home from his perfect high paying job. Willy Loman desperately wants this but the illusion of happiness is exactly that, and illusion. Willy was an unsuccessful salesman trying to catch the fast train to big money. Certainly the materialism is as rampant today as in the 1950's. Get rich quick infomercials still permeate the late night TV airwaves with countless "Willy Loman's" professing soul crushing ways to spend your last dollars. I think the conformity aspect has changed some. The 1950's were heavily steeped in the illusion of family happiness as a product of consumption and conformity. I think today is more about individual happiness as a product of consumption and money.
Come to think of it, even the popular show the Simpsons satirizes a Willy Loman type character. Gil Gunderson (usually referred to as Ol' Gil or just simply Gil) is an unsuccessful and unlucky businessman of Springfield. He has had a lot of failures Gil has held many different jobs, usually involving sales, all of which he either eventually loses due to an inability to perform or make any sales, or quits because something bad happens to him (for example, being shot in his first day as a bank security guard). I often thought that Matt Groening lifted Willy right out of the play and placed him in Springfield!
