I can only answer this from the perspective of a person in the United States. I don't know if you are asking about the US or some other society.
Here in the United States, we respect (above just about anything else) people who are able to make a lot of money. We see these people as the ones who have succeeded the most. We also believe that they make our society better by making our economy grow and creating jobs for others.
Because of this, managers or company executives are highly respected and are often listened to. It is an advantage in politics to be able to point to one's business experience. We feel that people who have succeeded in business are the greatest example what America is all about.
Power and respect that managers have can be attributed to two sources. First is the power and position they enjoy as a part of their job within the organizations they manage. Managers also receive some secondary power and prestige because of their position in the society in terms of their economic and social status.
Managers, are delegated many powers or authority to enable them to perform their work within the organization. This authority enables them to influence the actions and outcome of actions of many people. Managers exercise influence over the people they supervise is very clear. But managers also influence many other stakeholders of the company including customers, suppliers, shareholder and community in general. Because of this authority, others tend to treat them with respect avoid confrontation with them. This is the power managers derive directly from their jobs.
In addition, managers enjoy better status in the society for several reason. Capable manager with right combination of education and skills are not easily available. Also they have a substantial impact of the performance of the organization they manage. This increases the demand of good managers. Thus we are faced with high demand for managers with limited supply, leading to higher remuneration. This gives them more financial power. This also creates an image of managers as capable and successful people. This contributes to the secondary power and respect enjoyed by managers.