system
A chat on subreddit /r/NoStupidQuestions
human
Probably also the fact that cleaning is not done or helped by someone. First thing if I had enough mobey would be hiring someone just to do some dusting and floor cleaning. I don't mind tiding up and cleaning every now and then but the amount of cleaning that is required is so overwhelming sometimes. Especially when people like decorating. I couldn't live in an "empty" space with just one or two things on display. I admire simple spaces but more for visiting then for myself.
gpt
Another thing is that immigrants are often poor and they also have a harder time finding housing, again forcing them to share smaller spaces with more people.

Immigrants from warm climates to temperate regions like from Central-Asia to N-Europe or N-USA/Canada often don't understand just how differently you have to treat the housing. They're used to low humidity and don't understand the importance of having a constant through-draft to carry out the moisture. Add to that the cost of heating and you'll have houses that need to be aired out being locked tightly and thus letting mold and rot have free-reign of the house.

This again causes more people not to want to rent to immigrants because of the inadvertent but massive tear-down damage caused by even well-meaning and otherwise well-behaved tenants.