[zbuttram]

The issues in question here surface even with an empty city, at higher populations the CPU will almost certainly become the issue but right now most of the complaints are unrelated to sim performance and it even seems like for most people the sim performs quite well even at higher populations.

[VHRanger]

The sim performs OK, but it's still based on Game Objects to my knowledge (eg. All entities are a class type interacting OOP style)

A city sim could be made massively more performant using a data oriented architecture like Unity DOTS or any other ECS style engine