The American Middle Class Is No Longer the World’s Richest

a reply to: Cabin

S&F!

I concur and here is why ...

Hourglass economy

In the United States
Further information: Income inequality in the United States

In the United States of America the American middle class is being forced to either make it bigger or lose it all due to policy passed within the business model of capitalism as the United States knows it. Less borrowing to relatively risky businesses, less availability of making large capital gains as well as rising inflation. Commodities are at record levels, keeping the large companies maintaining record profits, while the middle class are paying more for all this, as the primary consumers of goods, and falling into the bottom of the hourglass, at least on paper.

Citigroup's analysts have labeled the American economy a “consumer hourglass economy.” The wealthy are doing fine, while the number of those living in poverty grows, and the middle is disappearing. New poverty figures show a big jump in the number of poorest Americans. Meanwhile, the middle class is disappearing says Andrew Leonard (writer @ salon.com).

The Hourglass Economy (salon.com)

I have bolded the three main factors according to wiki and I note that they would just compound the issues highlighted by the article linked in your OP!