Yes, we have always had homes, retreats or places where we went to relax, unwind or shut out the world. But we didn’t walk around the world like hermit crabs with our isolation surgically attached.
You know, I seem to remember an ancient Dave Berg "Lighter Side of..." strip in Mad Magazine making fun of the way people were isolated by their brand-new Sony Walkmans... twenty-five years ago.
That was (maybe) revolutionary. It introduced an entirely new experience to life: Listening to your own personal music collection outside your home. The iPod merely makes that existing experience somewhat more convenient. It's a quantitative, not a qualitative, improvement. No need to act as though there has been a fundamental shift in anyone's social interaction (or lack thereof).