The author is from Germany and still complaining about Americans interacting with each other less in public? I've been to Germany so many times and almost never seen anyone speaking to strangers on trains/buses/trams. Once I was on a train from Cologne to Frankfurt with a colleague and we were talking nonstop. After a while we realized it was just us talking and probably disturbing everyone else!
People go to extreme lengths to avoid talking to strangers on public transport even in developing countries. Earphones are just so effective.