There is history, hindsight, and playability. If the allied strategic bombers had only bombed German power plants they would have destroyed their production. No power, no factories. So we could include China with all its provinces and warlords and influence to follow history, but hindsight would have us take the most efficient path, and of course the playability would go down the tubes.
Just like playing a division level game of Global WW2 where each hex is a division, each plane counter 30-100 planes. That's a hell of a lot of pieces to move every turn.
So yea some things are abstracted more than others for better fun.