Many forces have shaped this deal, including technology, which replaced workers performing routine tasks, and globalization, which squeezed the margins of many businesses and exposed their workers to competition from cheap labor markets. And yet it would be a mistake to ignore the impact of a corporate ethos that has come to focus on rewarding shareholders and executives at the expense of any other consideration — be it workers’ welfare or even the company’s long-term sustainability. Indeed, workers today amount to little more than a line on the cost side of businesses’ balance sheets, with little claim to its prosperity.

Corporate profits have risen over the last quarter-century, as a share of the nation’s income, even as the workers’ share has shrunk. While executive pay has soared — padded with stock options and shares — the earnings of ordinary workers are below where they were in the 1970s. What’s more, the pensions that ensured workers a retirement perch in the middle class have been replaced by 401(k) savings accounts — which are cheaper for companies but put workers’ retirement prospects at the mercy of the stock market.

“How you divide the pie is a choice,” said Rick Wartzman, who heads the KH Moon Center for a Functioning Society at the Drucker Institute of Claremont Graduate University. “It is being carved differently.”

The change has happened across the board. In his book “The End of Loyalty,” published in May by Public Affairs, Mr. Wartzman lays out a shift in corporate culture both in success stories like Coca-Cola and General Electric and in less successful ones, like Eastman Kodak and General Motors. “For workers, the story was the same, whether they were working at a winner or a losing firm,” he said.

The good news is that it is not impossible to modify the behavior of the corporate leaders who have so drastically altered the contract with their work force over the last few decades. While it may be tempting to cast the new breed of executives as selfish villains who somehow lost their sense of right and wrong, the shift in their behavior responded to a shift in the incentives they faced. It was fed by a belief that snaked its way three or four decades ago from the halls of the University of Chicago through investment-bank trading floors and into the corner offices of corporate America: that the interests of corporate managers must be brought into tight alignment with those of shareholders. It was accompanied by one of the most destabilizing propositions in the modern history of corporate governance: This alignment was best achieved by paying corporate managers almost exclusively with stock.

Mihir A. Desai of Harvard Business School argues that this strategy amounted to outsourcing corporate compensation decisions to the capital markets — which have no way of telling whether the rise or fall in shares is caused by executives’ strategies or simply luck. This produced an enormous bubble in chief executive pay — which rose in tandem with the stock. It also made chief executives’ jobs more uncertain, vulnerable to market downturns. And it vastly distorted their behavior, putting every decision at the service of the share price at the close of the quarter.

Professor Desai points out that in the end, this structure does not really serve shareholders, at least not those with an interest in a company’s prosperity more than a few quarters down the road. “Capitalism seems to be serving managers and investment managers at the expense of shareholders,” he wrote.

Changing this behavior is not beyond the reach of policy. Just as changes in the tax treatment of executive pay in the 1990s encouraged stock-based remuneration, tax reforms might motivate corporate executives to invest for the long term rather than for an immediate stock bump — maybe even encourage stable employment and worker training. Until then, offering tax breaks to American corporations seems more likely to line the pockets of executives and shareholders than to improve their long-term prospects or the prosperity of their workers.