Auto-Generated Townie Takeover

While I understand auto-generated townies can be necessary to populate roles like vendors, mailmen, bar tenders, etc, surely they do not have to be the majority of sims everywhere. Whenever I travel, it seems at least 10 new auto-generated townies appear, which, while deeply annoying as I would rather see one of the couple hundred other sims that have been designed by a person, it's not the end of the world.

My problem is that my game created new auto-generated sims so obsessively that it deletes whole neighborhoods of non-auto-generated sims to make room for them. I will go to travel after playing a save for a little while, and suddenly, Windenburg, or Willow Creek, or any location I haven't been to recently, will be completely empty. Sometimes when this happens, I find the families in the gallery and am able to replace them, but of course, any skills, careers, relationships, etc that they had are gone.  

This is not an issue that stems from a mod. I have deleted all of my mods, and started over with brand new saves multiple times to try to get rid of this issue. The issue still occurred with all mods gone. It's not a mod. I have also tried using the repair function multiple times, in case it was an easy fix the system might catch, but that has been ineffective. I have tried placing every single non-autogenerated sim in my "My Households" section, then they were not deleted, but this overwhelmed my game and often led to crashes. I am currently trying to manage the issue by routinely deleting every auto-generated townie from "Other Households" before there comes to be enough of them that they supplant the much preferred original sims. It works sometimes, but it is not an ideal solution. Help would be much appreciated.