Straightforward and honest and a Polish immigrant to the United States, Stanley is representative of the new American who has "the Dream." He works on getting a promotion at his job, and his assertion of himself as "king" who has taken the aristocratic Stella and pulled her "down off them columns" points to the transfer of power in American culture to the one who works hardest for it.
This is not exactly a parallel, but certainly Blanche is representative of the increasing irrelevance of old aristocrats in the New South. Stella is, in many ways, her polar opposite- she opts pragmatically to stay with Stanley at the end of the play because she thinks that will be the way to a better future. Blanche is very much rooted in the past.