In the one-page summary of Elizabeth Warren's Accountable Capitalism Act, it says that “For much of their history, American corporations tried to balance the interests of all of their stakeholders, including employees, customers, business partners, and shareholders. But in the 1980s, corporations adopted the belief that their only legitimate and legal purpose was 'maximizing shareholder value.'” Is it true that corporations treated their workers better back in the 1950s, 60s, and 70s? Have any historians and theorists written about this in detail?