Fire regulations, plumbing regulations and so on are very strict, so internally you shouldn't really find any qualitative difference between Scandinavia and "other first-world countries".
In Scandinavia we have a strong affection for historic buildings, an affection that extends to interiors. We like fireplaces, creaky hardwood floors, crown mouldings, exposed brick walls, that sort of thing.
So buildings might feel distinctly unmodern, even though they aren't really. Some facilities may be lacking. Elevators are only common in somewhat newer (post-1980) buildings, for example. Common laundry rooms are usually pretty awful. And I have never come across a Scandinavian apartment building that has a porter.
But these are not important things. So again, based on what criteria are you judging Copenhagen?