Urban environments blunt people's connection to other people too, see

https://en.wikipedia.org/wiki/Murder_of_Kitty_Genovese

If you pack people in too tight they just tune each other out.

I mean, the very first paragraph of your own link says: "However, subsequent investigations revealed that the extent of public apathy was exaggerated." and the second paragraph says, "Researchers have since uncovered major inaccuracies in the Times article, and police interviews revealed that some witnesses had attempted to contact authorities."