Not much to work with here. It's in the Opinion pages, presumably because they don't have a section called "Evidence-based Analysis." If you already have an opinion on the subject, this article will do nothing to change it.

I perked up when I saw a paragraph begin with the words "Start with the numbers." But it doesn't have any real numbers. It says:

On average, Americans remain a lot poorer today than they were before the economic crisis.

I assume "average" means median, and "Americans" means "Americans who are not in the top 10%." We already saw that the level has been fairly flat since the '70s, and I gave some reasons why that may not represent a crisis.

This essay at least implies a reason we should be concerned about wealth diversity, something other than envy: "the continuing shift of income away from the middle class toward a small elite." But the mechanism by which this happened (to say nothing of if) is quite vague. Something connected to "rising household debt."

How are we supposed to come to any conclusions?

Then, the focus shifts from alleged economic damages to Americans to harms perpetrated against the political system itself. The commendable complaints against crapitalism -- distortion of markets by politicians under the sway of business interests -- would impress me more if they were at all specific. Instead, the author just says "government should be spending more" during "an era of mass unemployment."

It takes fifteen seconds to look up "unemployment rate in us" and get a pretty graph. Can you find the "mass unemployment" in this picture?

source

It's not hard to find an article arguing that inequality is exaggerated that at least contains a few citations.