It is though. You’re comparing apples to oranges - you can’t compare an FPS to a top down strategy. Even Cities 1 never had a great framerate, even 8 years later on modern hardware it still chugs, and it doesn’t have nearly the fidelity that Cities 2 has. The only reason the GPU is the bottleneck is because of the fidelity. If you turn down the graphics settings to Cities 1 level, guess what, the CPU becomes the bottleneck again.
For another example, Age of Empires 4 locks the zoom level because they couldn’t handle showing too much on screen. You just can’t demand the same rates as an FPS. Completely different parameters. You’re expecting an M1 abrams tank to have the agility of a honda accord and the speed of a masarati, when you really needed something something that could seat 20 people.