You might be confusing authoritarianism with leadership. The best CEO leaders lead by example and the ability to manage large complex organizations.  They must answer, usually quarterly, to a Board of Directors who have a fiduciary responsibility to make sure that shareholders expectations are met.  I have worked for CEOs who are authoritarians, and others who are great leaders, and there is a big difference even though there is always the potential for overlapping styles. 

 Trump would be the worst example of a CEO operating in a political environment if he were to be elected. He would be well-suited for a dictatorship because that matches his  management style,  but not a  governance system that requires collaboration and willingness to compromise. By comparison, even Hillary's GOP senate colleagues  acknowledge her ability to work across the aisle to get things done,  a hallmark of a good CEO leader.