... [T]he renowned Harvard economist, Larry Katz, who offers the most compelling analogy. “Think of the American economy as a large apartment block,” says the softly spoken professor. “A century ago – even 30 years ago – it was the object of envy. But in the last generation its character has changed. The penthouses at the top keep getting larger and larger. The apartments in the middle are feeling more and more squeezed and the basement has flooded. To round it off, the elevator is no longer working. That broken elevator is what gets people down the most.”
That's from The crisis of middle-class America by FT's Ed Luce.