At the end of the day, Miller makes it clear that luck and being liked are insufficient when ranged against the powerful forces that dominate the world in which Willy lives. This is perhaps clearly shown through the mythical figure of Dave Singleman, whose last name points towards the unique status that he has. Note how Willy uses the life and death of Dave to point towards the changes in the sales industry when he talks to Howard just before he gets fired:
In those days, there was personality in it, Howard. There was respect, and comradeship, and gratitude in it. Today, it's all cut and dried, and there's no chance for bringing friendship to bear--or personality. You see what I mean? They don't know me any more.
The economic system driving America, and in particular that is crushing Willy, is moving more and more towards an environment where "being liked" and "luck" will only take a salesman so far, and where impersonal relationships are more important than personality. Whether or not the audience believe Willy's claim about his former success as a salesman in his youth, it is clear that Willy just can't keep up in the present, and his failure is a result of an econonmic system that devalues and disempowers the individual, using them up and throwing them aside.
Willy didn't fail until he thought he was a failure. His job was too demanding, and he kept growing older. As his son Biff tells him: "You were never anything but a hard-working drummer who landed in the ash can like all the rest of them!" Willy has an enormous territory to cover. From his home to Maine is a distance of about 700 miles. Arthur Miller is not too specific, but it would appear that Willy drives all the way to Maine and back during the week and returns home late on Friday evening. That is about 1400 miles of driving in a cheap little car on a lot of narrow, winding roads in all kinds of New England weather. But he also has to do a lot of local driving in towns and cities. Then on Monday morning he apparently has to start out all over again. Just the driving would take up at least forty hours a week before he ever got to see anybody. He goes off with high hopes and comes back with disappointing results.
Miller does not really seem to know much about the life of a traveling salesman. He doesn't say if Willy gets reimbursed for the mileage he puts on his car, for his hotel bills, or his meals. Even if the company pays his expenses, he has a hard life, living in hotel rooms, eating in coffee shops, having to deal with all kinds of people, trying to be "liked." Miller provides virtually no information about Willy's business dealings with these New Englanders, who are famous for their thrift, provinciality, and rather dour personalities. Miller has Willy mention "buyers," but most of Willy's contacts would be small-time shopkeepers who did the buying, selling, and everything else. Only big stores and chains of stores have people who specialize exclusively in "buying." Willy is in a no-win situation. He has to cover too much territory and can't make enough money because there isn't enough time when he has to cover seven separate states. He can't demand more salary or higher commissions because there are too many people competing for too few jobs--and there are always younger people graduating from high schools and colleges and looking for jobs.
It's a cold, cruel world, but Willy thinks he will be successful because he is somthing special. He is not special. He's just a hard-working drummer who landed in the ash can like all the rest of them.