TO SWEDES - PLEASE READ (swedes only, please)

Many young people live like that when they get an apartment of their own.
They are privately run. In the big town centers they are expensive. And those are usually old.
Of course there's a lot of new construction but the movie shows apartments and buildings from places several hundred years old. The "island" buildings are from around 1700. The Stockholm apartments reside in buildings from early 20th century, and the exteriors seen in many places, for example those in Uppsala were Craigh visits a balcony he couldn't have reached in reality because the doors are very locked and guarded from the main street, those buildings are 18th century and the building atop the hill (Carolina Rediviva) is 16th century.
It's normal in a film which describes old family-dynasties to show such a landscape. And they also focused on gloomy looking street angles. The long narrow stairs shown in one shot certainly counts to that, and just beneath it Prime Minister Olof Palme was murdered by someone who easily escaped through those old and dark quarters.

One out of ten Swedes live in Stockholm.