During the Gilded Age, several key factors enabled industrialization in the United States, including abundant natural resources, a large and growing workforce fed by immigration, and major technological innovations in areas like transportation, communication, and manufacturing. Prominent industrialists and entrepreneurs in industries like railroads, oil, steel, and telecommunications helped drive economic growth through consolidation and vertical integration of their businesses. These business leaders were both admired as captains of industry and criticized as ruthless "robber barons" who exploited workers.