Well I am an american, so a lot of what I say is going to be US-centric, but I think in this case "first world-centric" would be more accurate. What I said applies to the first world, and most of the rest of the first world (western europe, south korea, japan etc.) is even more hyper-introverted than the United States. One of the biggest stereotypes that europeans have about americans (besides the whole "americans are all gun toting, bible thumping, obese, uneducated rednecks" thing) is that we're all supposedly chatty and extroverted.
Yeah, most of the third world is more extroverted than the US, but even then, I'd argue they're on the same trajectory to become isolated, atomized and hyper-introverted. They're like 10 years behind the US, whereas countries like Germany, Japan and South Korea are like 10 years ahead of the US on that trajectory.