Okay, let's get down to business:
Great men are important.
Because they can help us solve some problems very well, so that the world is no longer troubled by problems.
Ordinary people are also important.
Because there are only great men and ordinary people in the world, if there are all great men in the world, who will do the coolies (carrying and building houses)?
Actually, to be exact, ordinary people are more important. The world is created by human beings, but it is ordinary people who pay more physical strength.