On both sides of my family, my grandparents were immigrant Jews who tried to make a living as merchants. My mother's family settled in Bradford, Pennsylvania, a declining steel town. My father's family settled in St. Louis, Missouri.
The Great Depression was hard on both families. It hit the steel towns particularly hard. Meanwhile, my St. Louis grandfather went bankrupt and lost his clothing store in 1937. The Depression was the biggest event in my parents' lives. They were frugal, saving as much as they could--but not much in risky assets. We even lived in an apartment, not a house. But I did not grow up having to worry about money--my father's salary as a college professor seemed more than adequate for us.
The Depression also turned my mother and my father's older sister into Communists. My mother renounced her party membership in the 1940's, but my father's sister and her husband remained committed Communists until they died, even after the fall of the Berlin Wall. I gather that my uncle was a pretty effective union organizer, but he was kicked out of the unions when they purged their leadership of Communists. Their family lived in public housing in Chicago, since he had no source of income and she was often too ill to work.
Part of the post-1930's frugality was that we lived in a lower-middle-class neighborhood until 1964, when I was 10. I can remember the night that the neighborhood kids organized a fight on Carlo Reina's carport between a kid named Mike and my best friend Daymon (his mother named him that because he was born on a Monday, and Daymon is Monday spelled backwards). In that fight Daymon had his tooth chipped. I remember crying about it the next day, and my other good friend Gary asked, "What are you crying for? It wasn't your tooth."
When I was 11, we moved to Clayton, Missouri, which was and is the richest suburb of St. Louis. Thinking that I must be uneducated (because I did not have the privilege of growing up in Clayton), the school district assigned me to the low math track and to take a double period of English. By the time I got to high school, that nonsense had been sorted out. But I took away a lifelong belief that affluent people think way too much of themselves, and they are way too condescending and patronizing to everyone else.
There is serious mental illness on both sides of my family. Those aunts, uncles, and cousins who were least affected by it are rather affluent. Those most affected by it are not.
So I tend to associate poverty with mental illness. Perhaps I am overly optimistic about the economic prospects of those in good mental health. But my family's experience leads me to think that poverty in the United States is mostly a mental health issue. Leaving aside new immigrants, I do not see American poverty as being determined by social class.