In another likely scenario: Missing hiker without phone reception finally reaches the top of a mountain. The phone shows 2% battery and 1 bar. Finally! Immediately, his phone starts ringing. He doesn't know the number but dehydrated, hungry and with his last spark of hope he picks up. A familiar voice begins to speak: "Hello, I heard you have been in an accident that wasn't your fault..."
The state of PSTN direct-dialed voic comms in much of the US is such that legitimate phone traffic is 1/2 to 1/10 of all received calls. Channel saturation and abuse is such that people ignore phone calls, and quite often voicemail. If they have voice service at all.
Telephone service by any description in the form of "anyone, anywhere, can connect to any one, anywhere, at any time" is in increasing danger of abandonment simply because of nuisance and malicious harm costs. I've had repeated dicussions with individuals and businesses who are constantly pestered by unwanted calls, cannot distinguish legitimate from illegitimate traffic (see "Deep Fakes" voice impersonation being used in a recent bank fraud case, impersonating the CEO --- I've known people who've had fraudulent calls claiming to be known contacts), as well as endless scams.
The industry aware of this and raised the issue years ago. They do nothing about it:
[S]ince mid-2015, a consortium of engineers from phone carriers and others in the telecom industry have worked on a way to [stop call-spoofing], worried that spam phone calls could eventually endanger the whole system. “We’re getting to the point where nobody trusts the phone network,” says Jim McEachern, principal technologist at the Alliance for Telecommunications Industry Solutions (ATIS.) “When they stop trusting the phone network, they stop using it.”
https://nymag.com/intelligencer/2018/05/how-to-stop-spam-rob...
We've reached the point that people in possible need of rescue ignore attempts at contact, and ... with credible reason.