This is not necessarily tech driven. People are extroverted or introverted. Pre smartphone, when I was alone on the bus or subway, I always had my nose in a paper or a book. Now it's my phone or a Kobo. I didn't like and wasn't good at making small talk back then, and I don't think that has changed much. I feel like there are a lot of Seinfeld subplots built around avoiding social interaction that I really identified with.

On the other hand, I feel a lot of media is pushing us to ignore, suspect or otherwise be scared of strangers. I don't know that this is uniquely tech driven though.