Why some directors or CEOs don't listen except from department managers?and if that happens how to know there are qualified employees whom no one is taking care of them?

As the CEO learns how demanding it is to attend to the company’s outside constituencies, he also discovers, often to his shock, that he has to let go of a lot of responsibility—not just for operating the company but even for knowing what’s going on in it. The CEO can’t monitor everyone. It’s simply not possible for any one person to oversee every facet of a large company, even if he were willing to put in a 100-hour week. The new CEO may expect this to be true as he begins, but it still feels strange not to know what subordinates are up to, and many executives experience the change as a loss of control. One workshop participant recalled that he was stunned by the realization that he would have to rely on others in areas like operations, where he had previously thrived, and would have to master aspects of the company such as investor relations and regulatory affairs, where he had little experience. To be sure, the new CEO has the final say in hiring and firing, promotions, and compensation, but many of those decisions are, by necessity, in the hands of people closer to operations. Indeed, CEOs often end up knowing less about the operational details of their companies than they did in their previous positions.

its a good management practice within any organization , we can call it as proper channeling. But if there is exceptional issue or case, there has to be a procedure to to access or report to higher management. 

if are qualified and talented and if the do not use you and if you do not opportunity to excel, better to say good bye to organization and find good place 

One will notice some under performanceand grambling from the departmental heads, whom will look for ways of expressing their disatisfaction.

This is just a basic organization and management concept. In a business organization, there is what we called the levels of management. Try to search for it in google for further information.

to respect organization chart

and some worker need to show to top management he is work and like co

Each and every companies have their on policy on this regard, mostly it is part of organizational chart of any top management, employees could not explore on this case but the employee also one day will a manager then he will feel it. Why the employees are not allowed to contact the higher management directly? but when the employee became a manager then will know its important and why management implement such a policy.