All empires are based on cheap energy. Western Europe was not that advanced until coal could be used and it just so happened it was cheap and there was a ton of it. That's also one reason Europe is falling behind today... getting rid of all of that coal-fired energy.
Powerful nations are not smarter or more educated than the others... all that differs is the amount of cheap energy that is available. From slaves right up to oil.
You do make rather big steps....
Energy was available by different resources starting with sunlight for housing without heating and easy building materials from drying clay etc.
After that wood, then peat, watermill-windmill power, and finally coal and oil/gas.
All these sources only cheap available when either nearby centres of activity (by distance or good logistics like canals, streams) or later when for example the steammachine railroad made UK coal cheaply accessible.
But parallel to that food was a big driver.
The Middle East could develop fast because high yielding grain was available fast. China/Asia could only boom after high yielding rice was available.
France was better off than for example Germany in medieval time because the soil was more fertile in combination with more sun and enough rain. This changed when better crops were developed and changed significantly more when higher techs were developed for agriculture.
It is all the time the level of techs available and the availability of the matching resources, leading to all the time changing optimal areas for faster population, GDP per capita and GDP growth, resulting in military and trading power.
many small steps.
CIV as a game is reflecting that, although not perfectly ofc.
There is a lot of knowledge meanwhile available to get that modelled pretty good today. Archeologists apply economy models including crop yields from staple foods to calculate potential population size etc.
CIV as a game could be made much more realistic... but most people play it anyway in the military fashion.
AND on a side note the US area.
Too little streams or to much jungle to allow for really strong civilisations until the tech development allowed for good logistics to connect sweetspots of fertile soil, resources, etc.
And on that energy now... Europe has no big amounts oil/gas.
But the renewables will be a game changer for the whole geopolitical situation.
China and Europe big winners compared to for example the US who has lots of energy.
Sunlight renewables will make Marocco, Tunesia etc interesting areas nearby Europe.