How to get rich? Serve the rich consumer

As inequality grows, the wealthy account for a greater share of income and spending. But a new paper suggests that there is an upside to inequality for companies and workers that can best cater to the newly rich.

Nathan Wilmers, a sociology Ph.D. candidate at Harvard, looked at how the growing impact of wealthy consumers is reshaping the economy and wages. Others have termed this phenomenon "the plutonomy," or an economy in which earnings and spending are dominated by those at the top.

Consumer spending by the top 5 percent of households has grown 5.2 percent a year since 1989, while spending by the bottom 95 percent has grown at 2.8 percent, Wilmers said. In the past, economists have estimated that the top 5 percent of consumers account for nearly 40 percent of consumption.

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"The disproportionate growth of high-income consumers means that the U.S. economy caters increasingly to the preferences of elite spenders," Wilmers wrote.

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So what does this mean for the companies and workers?

Wilmers said that "the increased influence of these consumers sets up big rewards for businesses that create and sell the sorts of products the affluent want." Specifically, he looks at salaries for butlers, wine producers, Realtors, lawyers and bankers and found that those who are best at their professions and excel at skills valued by the wealthy have the highest wages.

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Even within the same industry—say, law or household staff—people hired by wealthy patrons make more than those that serve the middle class or affluent. Companies favored by wealthy consumers also have higher margins (as anyone who's looked at Hermes profits in Birkin bags can attest).

Wilmers' main point is that consumer spending worsens wage inequality, even within an industry, since there is a growing wage gap between those who serve the rich and those who don't.

Sectors of the economy that depend more on consumers making more than $150,000 a year have greater inequality of wages.

This may be true, but it seems a stretch to say inequality is to blame for the fact that the best lawyers, household staff and winemakers make more money. Better performance leads to better pay and higher demand. That seems to have little to do with the plutonomy.

But Wilmers said he controls for differences and that there is a growing earnings gap between similar products or services due in part to demand from the rich.

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For instance, he said butlers who manage household expenses and management for wealthy families make far more than cleaning staff who work for the middle class or merely affluent.

But isn't that just a function of higher wages for higher skills? A cleaning person cleans toilets; a household manager manages Excel spreadsheets.

There is a positive message in the data, however. As overall spending skews toward the wealthy, workers and companies who can best connect with the values and needs of the rich will see stronger earnings growth.

It doesn't mean we should enroll in Butler Boot Camp. But it does mean that bankers, lawyers, doctors, retailers, restaurants and even teachers who can best appeal to the wealthy will have the brightest prospects.

—By CNBC's Robert Frank.