It may not explicitly relate the material conditions on the ground, but it suggests a stratification that's unbecoming of an advanced country.

I thought this would resolve the discussion. I only care about material conditions on the ground. I am willing to define this broadly, to include access to refrigeration, self-reported satisfaction, highway safety, life expectancy, beer consumption per year, whatever makes people happy.

I am not much interested in the reputation or perceived decency of a country, which seems to me entirely a matter of opinion.

But then you mentioned a number of material conditions on the ground, stuff I do care about: people moving above subsistence level, plundering of the working class, despoiling of the planet. Public welfare, security and health. "Real problems everywhere."

You mention these real problems in abstract, non-specific language, without any explanation of how inequality is related, simply asserting that they are "utterly complicated" by concentrated wealth.

What is the evidence that income inequality causes bad outcomes, apart from tarnishing the reputations of advanced countries?

Your links sent me on a number of interesting rabbit trails. At the risk of complicating the conversation once more, I'll toss some back.

The income study showed satiation around $75,000 for "emotional well being" but "life evaluation" continued to rise with additional income.

When plotted against log income, life evaluation rises steadily. Emotional well-being also rises with log income, but there is no further progress beyond an annual income of ~$75,000.

After claiming that "inequality per se isn't a bad thing" b_b got me to read about the Gilded Age. It sounds to me like the best thing that ever happened to poor people: skyrocketing income, improvements in working conditions, new schools and hospitals.

On the prospects of advancing out of poverty, I find encouragement in the Census report behind the NPR article b_b shared.