In the Post War years, plenty of back-to-the-landers have taken the example of Thoreau, just as Kelly says (and did), but it is the less nationalistic dream of leveling and plenty for all that has been most meaningful in the last sixty years. Brin is a self-described libertarian who defends "social flatness" as a crucial element of "vigorous market competitiveness." But the American Dream isn't a dream of vigorous markets - for most of us (even for many of those on the far Right) capitalism is a nothing more than a mechanism, not an end in and of itself. The American Dream is consumerism - and its founding myth is Star Trek, which showed a future where social flattening and technology had ended poverty and (not inconsequently) where the great token of capitalism - money - was a thing of the past.
America became the first pax-power in history to deliberately establish counter-mercantilist commerce flows. A trade regime that favored the manufactures of many foreign/poor countries over those in the homeland. Nations crippled by war, or by millennia of mismanagement, were allowed to maintain high tariffs, keeping out American manufactures, while sending shiploads from their own factories to the U.S., almost duty free.