The vastness of China favoured the emergence of an overwhelming central power. In contrast to this great power, their subjects were immaterial, powerless and deprived of dignity. The subjects have to succumb to the great central power to sacrifice their lives, wealth and fortune, in order to help the rulers to acquire more lands, and to proclaim such acquisitions as their great achievements in history.
The subjects’ toil and sweat help the emperor and the bureaucrats to fulfill their lust, but they are not rewarded with prosperity in return, not even a sustainable life. The rulers would only make more wishes. What’s more, they would indulge in the inferno to struggle for power and wealth, by inventing more tricks and conspiracies to beat their enemies. What is the value of such lust? It would only drag the mankind into the dark age of civilization.
Therefore, the so-called “Unification”, is only a way to strengthen the power of the powered, the more unifications, the less restraints to their power. It ends up the powered acquires all the power, and the rest lose all their bargaining power, and become slaves.
You cannot say a group of people, though speaking different languages and living different ways of life as the “same nation” – only on the ground that they are placed under the same political system. For example, Australia, Canada and England are under the British Empire, speaking the same language, with similar religion and ideology. But even with these similarities you cannot say they are the same nation. However, the concept of “same nation” was carelessly adopted by the Chinese.
To say it more plainly, there are some rulers who are just not capable to rule the population and landmass with such great variety, yet they are not shy to call themselves a great power. In reality, their mindsets can only understand a country like Korea which consisted only of a single “nation” speaking the same language. It’s just like a primary school student grumbling the examination paper being too difficult. It’s not the fault of the examination paper.