Hmmm.... It's my experience that there are people at all income levels who purchase things that they really cannot afford. I usually attribute it to a failure to defer gratification for purposes of accomplishing more important goals. I didn't view this behavior as being only associated with the "underclass".
rwfromkansas said: "There is also a fear of kids doing better than their parents, which is completely different from middle class."
I don't understand what you are describing. Fear on whose part? The kids? Can you elaborate on this?
Yes, they are just generalizations, not true for everybody.
But, they have been proven true most of the time from my experience and that of other teachers.
As for the fear, I mean poor parents are afraid of their kids doing better than they did because they often depend upon them for extra money etc.