I think this would add to the immersion, seeing some visual explanation of how NPC's are communicating with each other long distance, in other cities, miles apart from each other.
I'm not expecting NPC's to be walking around with smartphones and androids, or even being able to use an in-game phone like in GTA V, but this is an obvious technology that should be acknowledged. Especially since the Fallout universe is based off an alternate future reality that takes place 200 years after the 50's.
Post war technology has radio broadcast signals, power armor, computers, vertibirds, laser muskets and more, but no evidence or working phones or any form of long distance voice communication.
It would be cool to at least see NPC's from time to time using either their Pipboys, or some sort of landline or mobile phones, maybe even walkie talkies to communicate long distance with each other. Perhaps even using your Pipboy to make and receive calls from in-game NPC's from time to time would be cool.