This post from Matt Yglesias, under the Buzzfeed-worthy headline “One paragraph that explains why the American economy’s [sic] isn’t working for the middle class,” is an excellent explainer, if what you need explaining is why you’re not reading Vox.

Mr. Yglesias is worked up by the fact that many publicly traded corporations recently have been allocating relatively more funds to dividends and stock buybacks, and relatively less to investments in plants and equipment. “If every business acts like a piggybank for rich shareholders rather than investing in the future you have a huge problem,” he writes. “The status quo is fine if you happen to already own a giant pile of stock. You’ll keep getting paid out of high profit margins even if there isn’t much growth. But for people who work for a living it’s a terrible outcome.”

Set aside the fact that there are very many shareholders who are not rich — major institutional investors such as CalPERS and the Civil Service Retirement and Diability Fund manage hundreds of billions of dollars on behalf of teachers and meat inspectors — but do consider the magical thinking behind the assumption that there will be “high profit margins,” simply because . . . magic!

Mr. Yglesias is right to be concerned about the lack of investment in capital goods, something that worries me a great deal. That is why it is so disappointing that he does not consider the obvious question: Why are businesses apparently hesitant to make long-term investments in things such as factories and new equipment?

There is an answer to that question, but gird yourself: It requires a bit more than one paragraph.