This game never needed a more human and belivable city, because it clashes with the concept it tries to show (no, its not cut because of the time travel woobley thing you say). It needed to look like a giant beautiful diorama, and they accomplish this perfectly. Its like Disneyland's Main Street, a very beautiful place, but its only a facade (I dont mean Disneyland in a twisted sense like in Infinite, in Disneyland is a facade because its only a park that wants to bring americana childhood memories not a city for people to live, while in Infinite it serves a real and dark purpose), it would never work in real life, thats why even if despising other races, they still need cheap human labour for the thing to work.
The beautiful architecture is only something to hide the horrible society that lives in there.