I don't understand why this is even a bad thing. A larger proportion of families with children are living in high income areas? That sounds like great news! By itself, isn't this just a straight-up improvement with no downside? Isn't this exactly what we would hope for, that more people are "wealthy" than before? That's the opposite of increased concentration of wealth, when looking only at quintiles. The only worrying information in the article is that the percentage of families living in lower income areas has also increased. I think that information deserves much more attention. Focusing on the fact that a larger percentage of families make at least $110,000 just sounds like envy to me.
Right. The article is written as if there's a conspiracy among high earners to lock others out of a stable family structure. Average intact families with children make an average of >$100,000, putting them squarely in the fourth quintile, and certainly able to get medical care and education. For a two income household to make $100,000 only requires that both partners have an ok job. It's as if the thesis of this op-ed is that the government should enact policies that discourage people from getting married for the sake of "equality". I get that inequality is an important issue, but just pointing out that people have varying incomes does little to nothing to answer why inequality is detrimental or how it can be addressed, not to mention why it's been widening in recent decades.