And that’s exactly what happens.
Research indicates at least three causal pathways via which inequality constrains opportunity for those at the lower end of the economic spectrum.
First, inequality is driving increasing residential segregation by income. The shares of families in neighborhoods of concentrated poverty and neighborhoods of concentrated wealth both more than doubled between 1970 and 2009, while the share of families in middle-income neighborhoods declined from 65 percent to 42 percent. Those high-poverty neighborhoods—where more and more families are living—create lasting disadvantages for many who grow up there: If a family with young children (less than age 13) relocates from a high- to a low-poverty neighborhood, the kids achieve better academic and economic outcomes later in life, as new work by Chetty et al. indicates.
Second, inequality leads to unequal access to quality educational experiences throughout a child’s lifetime. Over the period of growing inequality, these disparities have increased. In 1995, for example, families with education debt in the bottom half of the net worth distribution (a broader definition of income, including assets minus liabilities) had a mean debt-to-income ratio of around 0.26, meaning that for every dollar of their income, they owed 26 cents in college debt. For families in the top 5 percent, that ratio was eight cents on the dollar. But by 2013, the debt-to-income ratio had more than doubled to 0.58 for the bottom half (some of whom are poor but many of whom are middle class) while remaining unchanged for those at the top.
Third, and most importantly, inequality directly undermines equality of opportunity, likely through a variety of mechanisms. As the gap between the rich and poor widens, lower-income families have less ability relative to their rich counterparts to invest in enrichment goods for their children. Children from families with less income have relatively less extensive and privileged social networks and, compared to their rich peers, are more likely to experience the type of "toxic" stress that can hamper brain development and long term academic, health, and economic outcomes.
In short, inequality entrenches immobility not just by enabling increasingly unequal transfers of wealth from one generation to the next, but also through a number of more subtle pathways that affect opportunity on a daily basis. It may not yet be possible to explain all of these subtle pathways with great certainty, but the fact that “rich and poor children score very differently on school readiness tests before they enter kindergarten” should be viewed as an unsurprising consequence of the high levels of inequality American society currently tolerates.
Members of the “don’t-mess-with-the-rich-to-help-the-poor” crowd also ignore the political dimension of inequality. While Rubio, Paul Ryan, and others are professing their concern for the poor, they’re busy trying to repeal the estate tax (at a cost of $270 billion over 10 years) and writing budgets that gut the safety net. These policies restrict mobility at both the bottom and top by exacerbating the burdens of being poor, increasing the privilege of being born into riches, and eliminating revenue sources for investments that might begin to reverse the inequality of opportunity. Why do politicians pursue such policies? Because they are nudged along by the interests of wealthy donors. Inequality begets greater inequality.