It is a somewhat accepted rule that the most well received games are those that reward the player, and when it comes to 4X games, that sense of reward is usually linked to build a great empire successfully.
However, in real history, the greatest empires don't last for long: Rome, the Mongols, Spain and Britain all fell (even USA may be included here in the close future, as the sphere of influence most of its richness comes from is either falling or highly menaced). Eventually the social or economic conditions (or both) would change so much that the state could not preserve its capacity to control all its territories, be it to internal or external enemies (of the state). Sometimes the incompetence of the government played a factor, but sometimes it was inevitable due to how the state had to be established.
Given this, a game that pretends to be realistic must simulate historical changes that inevitably leads to the fall of empires, and thus, what the player has built.
How could such a game be fun?
However, in real history, the greatest empires don't last for long: Rome, the Mongols, Spain and Britain all fell (even USA may be included here in the close future, as the sphere of influence most of its richness comes from is either falling or highly menaced). Eventually the social or economic conditions (or both) would change so much that the state could not preserve its capacity to control all its territories, be it to internal or external enemies (of the state). Sometimes the incompetence of the government played a factor, but sometimes it was inevitable due to how the state had to be established.
Given this, a game that pretends to be realistic must simulate historical changes that inevitably leads to the fall of empires, and thus, what the player has built.
How could such a game be fun?