Perhaps the most useful advice for someone who aspires to material success is to develop expertise at a task that others value. Such expertise comes not from luck but from thousands of hours of assiduous effort.

But talent and effort are not enough. Luck also matters. Even the most able, industrious people in South Sudan have little chance at success. Success is not guaranteed for deserving people in wealthy countries with highly developed legal and educational institutions and other infrastructure, but it’s substantially more likely.

Being born in a good environment is one of the few dimensions of luck we can control — that is, at least we can decide how lucky our children will be. But as a nation, we’ve been doing a bad job of it for at least a generation. The luckiest are getting luckier even as their numbers shrink. The unlucky population is growing, and its luck is getting worse.

These changes have stemmed in part from sharply diminished public support for education. According to a 2015 report by the nonpartisan Center for Budget and Policy Priorities, for example, state spending per student averaged about 20 percent less in 2014-15 than in the 2007-8 school year. More than 70 percent of students who graduated from four-year colleges in 2015 had student loans that averaged $35,000.

It’s no surprise, then, that access to the benefits of a college degree continues to depend heavily on family income. According to a study from the Alliance for Higher Education and Democracy, at the University of Pennsylvania, and the Pell Institute for the Study of Opportunity in Higher Education, 77 percent of offspring of families in the top income quartile had earned college degrees by age 24 in 2013, compared with only 9 percent of those from bottom-quartile families. More troubling, the disparity persists even when controlling for precollege academic aptitude scores.

The human tendency to underestimate luck’s role has contributed to this troubling state of affairs by reducing the electorate’s willingness to support the public investments that make economic success possible. But the taxes people want to avoid need not be personally painful.

Evidence from the social sciences demonstrates that beyond a certain income threshold, people’s sense of well-being depends much more on their relative purchasing power than on how much they spend in absolute terms. If top tax rates were a little higher, all homes would be a little smaller, all cars a little less expensive, all diamonds a little more modest and all celebrations a little less costly. The standards that define “special” would adjust accordingly, leaving most successful people quite satisfied.

Happily, there is a simple remedy: Merely prompting people to reflect on their good fortune tends to make them more willing to contribute to the common good, according to a 2010 study published in the journal Emotion. So try to engage your successful friends in discussions about their experiences with luck. In the process, you may increase their willingness to support the kinds of public investments that will enhance the next generation’s odds of success. And you will almost surely hear some interesting stories.