I'm guessing the engine just wasn't capable of complex logic. It was single thread limited, so I'm guessing adding any kind of complex logic would require a huge change just to set up threading so performance doesn't tank, to the point where they might as well make a new release.

My understanding is that this release was supposed to fix that underlying code so it could support much more complex computation without killing the render loop. I don't have any specific statements to prove that, other than them saying you'll be able to make as big of a city as your hardware can handle.

So that's why I think it's feasible to add later. But you're absolutely right that they haven't done that in the past, so I could be reading between the lines incorrectly.