> Such worries probably occur with every generation (and newer technologies) and things tend to turn out alright.
Do they? I think we just get used to the way things turn out, and thus think of it as "alright", no matter what actually happens.
But consider: everyone knows there is an epidemic of obesity in the U.S. Is seems unlikely that the rise of sedentary screen-oriented activities -- beginning with television -- is not a contributing factor.
Another: since the advent of the telephone, people have been visiting friends less often. Why visit, when you can talk any time you want? But look around on the web, and you'll find an enormous number of articles on how our world is now filled with lonely people. Again, a connection seems likely.
EDIT. A pre-emptive strike on a rather obvious objection: No, I don't want to go back to a world without modern technology. I like being able to learn about places I don't go, talk to people far away, etc. But let's not claim that modern technologies come without downsides -- often big ones -- and let's not dismiss any concerns as mere alarmism.