Do you think that the staff who work extra hours in office are loyal, hardworking & efficient? And company should relate its success to them?

Yes,But not on all case.

If staff is loyal and hard worker then company success related to them.

No. Employee should manage their time better. Efficient workers do not spend long hours with exception to those days where one may have extra work. Organization should always encourage work-life balance and never reward employees who are habitual long hour workers.

Not at all. An employee should learn to manage the work within given time. There are only some exceptions when all the team is working on some critical projects. Beside that the late sitting should not be encouraged. 

There is no one definitive answer.  It might mean that they take on too much work (their fault).  It might mean that they are given too much work (manager's fault). It might mean that something has gone wrong beyond their control and they are working to get it back on track to meet a deadline. It might mean that they are passionate about their work and enjoy what they are doing. I might mean that they don't have a social life and are substituing work, which there is nothing wrong with if they get satisfaction from it.  To say that they are not able to finish their work is a shallow perspective on the situation.

No, it means they are not able to finish thier work on time and they are not at the time managment 

No, to me this means they did not complete their task in the given time, it means they are not at time management.