They do indeed talk to people in other timezones as well. We may have online meetings sometimes, with at least three timezones involved.

I can't see how one would only contact in touch with people in a single timezone, unless one only wants to have contact with people in continental Europe (excluding e.g. Portugal and Finland), or people in a single timezone in the US. Timezones are everywhere. The earth is a sphere, so.. can't be avoided.

If your work involves coordinating across timezones daily, you're part of the small minority cases I was talking about. Offline world is still mostly local, and almost all interactions almost everyone has, online and offline, are local too.

Firstly, that's not a small minority case, and secondly, in my small town there are people from around 100 nations, and they have family and friends from all over. And, as I said, even central Europe has 3 timezones just inside EU. It's not like most people only have contact with their 50 neighbours, and never go anywhere. When I talk with friends, timezones come up reasonably often. It's not something people can walk around and not be aware of.