No, it's not. Just by virtue of there being more people in a big city, there would also be shittier people. Sure, there are also more good people, but the shit always rises to the top.
I don't remember anyone from NYC making eye contact or talking with anyone the times I've spent there. I know on the subways, it was "look down at the floor, put on my headphones, play on my phone, ignore everyone and everything." I have no idea where this big, friendly world you are talking about exists. It seems a bit rose colored to me.
rex.