Well, one key difference is that the immigrants of the 20th century had the fortune of being alive in a time when the U.S. was in its most prosperous century. Government spending in these working and middle class white neighborhoods was an open checkbook. These areas were also green lined by banks, (as opposed to communities of color, which were mostly shut out of the opportunity to own homes and accumulate wealth through them). This is why so many Irish and Italians were able to bolt to the suburbs. I'm not even saying these communities didn't have cultures that prided themselves on organization and cleanliness, I'm just saying they had a lot of help that people of color did not.