 He dismisses the idea that bursts of productivity resulting from technological advances can be relied on to return sustained economic growth; we should not expect "a more just and rational order" to arise based on "caprices of technology", and return on investment can increase when technology can be substituted for people.The book's exceptional success was widely attributed to "being about the right subject at the right time", as "The Economist" put it.Piketty himself recognized that there is a common sense "that inequality and wealth in the United States have been widening."