This is not a sufficient statement of a manager's basic responsibility. It is certainly true that managers should work to focus their employees. However, their most basic responsibility is to set up a system that will allow work to be done efficiently and effectively.
A manager's most basic responsibility is is not to get their employees to focus. Employees should be able to focus on their own without being motivated or pushed by the manager. What the manager must do is to create an organizational structure with plans that will ensure that the desired outcomes can be achieved. Motivated employees who do not have a well-structured and well-planned system will have a hard time achieving the firm's objectives. Therefore, what the manager should do is to create an environment in which workers can achieve their objectives. Occasional motivation and focusing may be needed, but that should not be the most basic responsibility of the manager.