It is very strange, the difference between the cultures. I wonder what happened to the small-talker cultures that caused this weird social protocol to emerge. Or, the other way round: what happened to Finns and the like which suppressed the development of small talk?
It's a societal preference, too, not necessarily individual. There are plenty of folks in small-talking countries who hate small talk. I'm not one of them, but I can see why they hate it. If you look at it through a cynical lens, it really is entirely mechanical. It's like a TCP/IP handshake for human beings.
I bet there are Finns who want to small talk too. We should set up an exchange program for the talkative Finns and the reclusive Americans! They can take each other's places, and everyone will be happy :)
I think what happened to the Finns was living in a very cold climate causing them to have to spend a large portion of their time indoors. In past centuries or millenia "indoors" meant the inside of a small cabin. That cramped space was often shared by a fairly large family by modern standards, which would have been intolerable without honing the skill of studied indifference. Such long-standing cultural practices do not change overnight.
But there are signs of that culture slowly dying out. These days, television is filled with constant inane babble, hugging and incessant small talk. Individual sports are no longer where the Finns are the most successful at. Ice hockey has been the de facto national sport for a couple of decades now. In basketball and volleyball, Finland has been able to do surprisingly well in international tournaments in recent years. In sports, Finland is becoming the new Sweden.