> Warren’s central argument in the book is that this rise in household income was almost entirely driven by the increase in the number of two-earner families. And adding income by adding a second worker, she argues, has very different economic implications than rising pay for a single worker. In practice, the book says, the increasing ubiquity of two-earner households leaves families in more precarious financial circumstances with more brittle budgets that were more prone to tip over into insolvency if a problem cropped up.
> The “two-income trap,” as described by Warren, really consists of three partially separate phenomena that have arisen as families have come to rely on two working adults to make ends meet:
> The addition of a second earner means, in practice, a big increase in household fixed expenses for things like child care and commuting.
> Much of the money that American second earners bring in has been gobbled up, in practice, by zero-sum competition for educational opportunities expressed as either skyrocketed prices for houses in good school districts or escalating tuition at public universities.
> Last, while the addition of the second earner has not brought in much gain, it has created an increase in downside risk by eliminating an implicit insurance policy that families used to rely on.