Just read the article and was amused that Nina Munz FitzGerald's building, Plaza 400, is where my late Aunt Rose lived. I didn't know it was such a thrifty choice, but I do recall that rooftop pool and the social life Rose used to talk about there.
In my experience, bigger buildings can be more social and friendly than smaller ones, where people seem to guard their privacy more. I lived in an Upper West Side brownstone rental for a decade, and hardly ever interacted with anyone else there, whereas when I lived in a coop with 234 apartments, there was a lot of socializing among the young parents, there was a building book club, holiday celebrations, etc.
And now here in JH, we are again in a very small building, where people are polite, but not really friendly or social with one another.