Please remember to not take the game economy too literally.
For performance reasons the game economy is a bit weird.
For example when I was trying to do an economy mod, I found out the game actually tracks the fact a planet size 8 is consuming millions of food units, not "4000" or something like that, but for performance reasons this is not displayed.
For example when calculating trade between markets, the game calculates all trade, but spawns ships only ocassionally, to represent that trade and allow players and pirates to prey upon the convoys. If you changed the game source to actually transport all goods physically, it would need to spawn thousands of fleets when dealing with markets size 8+ and would run really slowly.
Another thing about scale: remember Persean sector is not THAT populated as some people think, even with tons of faction mods installed, the total population when the game starts is about 2 billion people, most of that population is in Chico actually (someone once did a graph, something like 45% of everyone is living in Chico alone).