money doesn't buy happiness but happiness buys money?

Newsweek has an article on how "Americans who earn $50,000 per year are much happier than those who earn $10,000 per year, but Americans who earn $5 million per year are not much happier than those who earn $100,000 per year." But it's this parenthetical that made me chuckle:

(Curiously, although money doesn't buy happiness, happiness can buy money. Young people who describe themselves as happy typically earn higher incomes, years later, than those who said they were unhappy. It seems that a sense of well-being can make you more productive and more likely to show initiative and other traits that lead to a higher income. Contented people are also more likely to marry and stay married, as well as to be healthy, both of which increase happiness.)

On a related topic, Penelope Trunk quotes David Blanchflower, professor of economics at Dartmouth College: “Going from sex once a month to sex once a week creates a big jump in happiness. And then the diminishing returns begin to set in.” He adds, to the joy of all who are underemployed, “It’s true that money impacts which person you marry, but money doesn’t impact the amount of sex you have.”