Bigger cities need booth more in-game electricity and real-world electricity, it seems.

I don't know how often I've looked at combinatorics and yet I still harbor a secret belief that you can pre-calculate a hell of a lot more than we do and just use the result when the time comes.

Its like part of my brain lives in an alternate universe where some entire field of dynamic programming has flourished that we don't (or categorically couldn't) have here.

When I think of the fan spinning in Skylines I am transported to a memory of staring at an empty chunk of ground, watching the trees blow in the wind, and wondering if they really needed to be calculating this just right now.

There are tricks you can do with animation cycles where if all cycles are relatively prime, then the pattern only repeats every few minutes, hours, centuries. It's part of why we have 13 and 17 year cicadas. They align on a frequency of over 2 centuries, and they have near misses (appearing in successive years) around every 50 years (with a conspicuous 118 year respite in the middle that has me wondering about how public policy and cicadas work...)

> There are tricks you can do with animation cycles where if all cycles are relatively prime, then the pattern only repeats every few minutes, hours, centuries. It's part of why we have 13 and 17 year cicadas. They align on a frequency of over 2 centuries, and they have near misses (appearing in successive years) around every 50 years

You didn't explain how this observation fit into the rest of your comment, but if you're saying that putting two things on simple cycles is good enough to look acyclic to players, I don't think that's true. If you have an oak tree and a fir tree next to each other, animated in 13 second and 17 second cycles, and it takes four full minutes for the oak+fir system to repeat itself... people will still notice that the oak tree is on a 13 second cycle, and the fir tree is on a 17-second cycle. There's no rule that says you can only consider things in the context of everything else that might happen to be nearby.

I don't think it's the animations in cities: skylines that makes it a CPU-hog, I think it's the actual simulation of the various agents pathfinding, etc.

No, tried the other way, impossible to play even on lowest settings. Try Factorio, it's 2D and runs smooth as butter on my laptop.

I highly recommend the factorio dev blog for anyone interested in game development - they do some amazing stuff to performantly simulate millions of discrete particles simultaneously. My 10 year old macbook can run ~10k autonomous robots before I start seeing any slowdown.