The original cities skylines had atrocious performance after a certain city size as well, especially on hardware available at launch. Hopefully they can deliver on better performance over the next few months, I expect it to improve before they do their console release.
Assuming you are talking about in the US, shelter is included in inflation calculations. You can argue about the methodology, but the cost of having a home is in there and does contribute to inflation. It is about 30% of the overall basket.