The issue of why class politics, as such, have not taken a strong hold on the United States is much debated by socialists, Marxists, etc.
Here are two theories with which I'm familiar:
+ The vast resources (through the land itself and, later, through global power) of the country have helped to temper class resentments.
+The racial divide has prevented a strong unification of the working class.
Its interesting to note that the United States has long (since, at least, the late 19th century) had a relatively large proportion of "tertiary workers." This categories those who are neither owners of capital nor "professionals" nor factory laborers but who work, for instance, in "offices, shops, and services" (Hobsbawm, "The Age of Empire," p.115. New York: Vintage, 1989.)
Historically, such tertiary workers tend to be less class conscious than, say, factory workers and certain segments thereof tend to be open to cultural appeals for purity and righteousness.
A certain segment of the labor movement (Change to Win, since 2005) under the leadership of the Service Employees International Union has, in recent years, refocused efforts to organize the type of service workers that, in various forms, characterize American labor history. They have had some success but the jury is still out on whether a strong labor movement can be built from that millieu.
What's your point of view? What's the future of America's working and service classes?