Except that workers did not go to the same job every day, nor did they return to the same house when they were done. No sim has a history; every move was to the

Except that workers did not go to the same job every day, nor did they return to the same house when they were done. No sim has a history; every move was to the first available location that an invisible "seeker" agent found. So, by not having history, more agents had to be used in order to find available locations. Not to mention that water and electricity were basically implemented as "wandering" agents that just randomly walked the grid and "deposited" at every location they passed until depleted. Which, in turn, meant even more agents, because they had to be populous enough that the random walking would ensure visiting the entire grid. TL;DR: There were a lot of decisions SimCity made that directly increased the number of agents required. This in turn directly impacted the #1 issue about the game: City size.