How Realistic is Civilization?

After playing the game for a few weeks now and catching myself playing for 3 hours in a row without realizing it, I am advancing pretty quickly in the game. I am the leading civilization, and have been throughout the entire game and have been since I started. I am currently in the 18th century. In reality how many civilizations begin as the most powerful and held that power for that length of time. None. Not the Greek Empire, Roman Empire, the Persians or the Egyptian that all at one point were at the top of their game. While empires like Japan and China have survived the length of time, they never were the top civilization. Because of this I am beginning to wonder how realistic the game is? Yes you can give your cities different names, but historically is the game accurate? For example in one of my cities currently houses the Parthenon, the Scottish Yard, Versailles, Palaces Stone Henge, The great library, an Academy to a great scholar, The Sistine Chapel, and Oxford University, and I am currently working on the Statue of Liberity amongst other things. It houses all this while producing both a strong military / naval forces and while building factories and industrializing my cities. In the world today all of these famous national landmarks exist. However some of them don’t even exist in the same country, so why is it that I have the ability to build them all in one civilization? I just begin to wonder, how long could a city really remain this powerful in reality without falling apart.

The Roman Empire eventually failed despite its apparent sophistication eventually. It lacked taxes and simply ran out of wars to fight, land to conquer and consequently their economy weakened making in vulnerable to invasion. I begin to wonder…why has this yet happen to my Civilization. I am not going out and conquering the land as the Romans did. But in reality why has not another civilization invaded my territory or attempted to? In all the years my civilization has now “existed” in reality with its wealth and power it would not go untouched for so long. I just begin to think it is unreasonable. Civilization does a great job of teaching you about empires develop and finding a balance between culture, religion, protection, food and development. However I think in the aspect of going to war, nations invading or lasting to the extent that mine has I am not sure if it true to the real world.