The question left unanswered in this article is why are wages in the US falling relative to productivity?
Since wages are the "price" of labor, and prices are set by supply-and-demand, falling wages imply either (1) an increasing labor supply or (2) a shrinking demand for labor (or both). So here are some specific reasons for stagnating US wages:
INCREASING LABOR SUPPLY - Slave labor, prison labor and child labor in countries like China. - Immigration from Latin America after NAFTA. - Liberated women entering the paid US labor force starting in the 70s.
DECREASING DEMAND FOR LABOR - New labor-saving technology, computers and robots that work faster, better and cheaper than humans. - Financialization: Investors can make more money from asset bubbles in housing, bonds, and dollars than they can from labor. -- ZIRP: With real interest rates heading to zero (or less), why should I continue to pay high interest on the money I borrowed a decade ago to build this US factory? Liquidate the factory, fire the workers, and relocate somewhere cheaper; or better: simply use the money to buy bonds and bet on falling interest rates. -- High housing prices: An employer needs to pay his workers subsistence wages, which means enough to buy a place to live, but with housing prices so high, this is impossible. Better to bet on the housing bubble than buy labor.