Why were John d Rockefeller Andrew Carnegie and JP Morgan called captains of industry?

John D. Rockefeller, Andrew Carnegie, and J.P. Morgan were called "captains of industry" because they played pivotal roles in transforming the American economy during the late 19th and early 20th centuries. They were instrumental in the growth of major industries—oil, steel, and finance—through innovative business practices and strategic investments. Their efforts not only led to the expansion of their respective companies but also contributed to the overall industrialization and modernization of the United States. Moreover, their philanthropic endeavors later in life further solidified their legacies as influential figures in American history.