The cellphone was invented after that and has forever changed the way we reach people and fundamentally how they are reachable.
Do you remember life pre-cellphones? When you left your house you literally dropped off the map. There was no way of anyone knowing where you were or where you were going. Unless you let them know beforehand, there was no way for people to catch-up with you when you got there. All sorts of tiny events required massive planning.
Now when you leave the house, should you so please (and the vast majority do) you can be reached. Climbing a mountain? In another country? Nobody knows this? They can still contact you! You can be at a place you've never been before and your friend can contact you and meet you there!
I actually think this disrupts my zen a little bit; I'd rather not be reachable at all times. I rarely pick up my phone - maybe for my father, my brother, or my girlfriend. Everyone else can leave a message.