I do not know why this hasn't been fixed, You can so clearly see it when other people are playing, for example the sim Supply's super sim Let's Play, he has so many City Living sims in his save now.
I am using mods to deal with this, I am downloading sims from the gallery and putting them in unplayed households, then I have MC Command Center, population set to 0 for everyone and then I am using NPC Control by Paulson. By doing this the game generates much less sims and uses existing ones instead from your unplayed households. So I have sims that I have downloaded from the gallery showing up on the street and as workers instead of generated city living sims.
https://i.imgur.com/GVPTOCe.png
