This is certainly a class issue, but ethnicity?  I'm not sure about that.  If my parents made do with what 1970s Toronto grocery stores had, then new immigrants can today.  Besides, produce can be "ethnicized" in every way possible.  Same with many grains.  I regularly make fried quinoa or "riced" cauliflower and when I was little, my grandmother would substitute gai lan or choy sum with spinach (even though it wasn't even all that close).