“Tangible material wealth is only a conversion of pre-existing physical material into a form that is more valued by human beings. The ability [the skills] to do so is the real wealth [which is called human capital].
“Behind such skills are cultural values that give a priority to the acquisition of those skills — and new skills as the old ones become obsolete over time, making the mastering of new skills imperative.
“Different groups living in the same external environment can have very different productivity if their internal cultural values produce very different priorities as to what they want to do, and at what sacrifices of other things.”
~from Wealth, Poverty, and Politics, page 96-97