As a rule, from what I've observed, the American captain of industry doesn't do anything out of business hours. When he has put the cat out and locked up the office for the night, he just relapses into a state of coma from which he emerges only to start being a captain of industry again.
The quote highlights a perception about American business leaders, suggesting that they are intensely focused on their work during business hours but completely detach from their responsibilities once the office is closed. This characterizes them as being almost robotic, going into a sort of hibernation where they do not engage in any activities related to their work after hours.
This viewpoint implies a lack of work-life balance among these captains of industry, depicting them as individuals who are only alive to their roles during the official workday. Outside of those hours, they seem to become inactive or disengaged, signifying a devotion to their business that leaves little room for personal life or leisure.
