An element of our younger siblings' (Gen Z) entire culture is a fear of/avoidance towards making and taking phone calls. Network-effect ecosystems have grown and developed because POTS is so bad.
The only people left with landlines that lack caller ID and 'suspicious caller' filtering are the elderly, where they're continuously preyed upon by spammers.
A shame, since if there was one thing the landline phone network was, it was reliable - in a way that cable can't even hope to match. Too bad that it got to be reliable for scammers as well.
This isn't the network losing relevance, she's literally still using it. She's just gatekeeping with her contacts.
I'm not saying we don't need to clamp down. But the downside of clamping down too hard is the calls from contacts in her address book not getting connected. That, and HN being littered with stories about people who are--for some random reason--unconnectable due to no fault of their own. That's the natural response if you let the "throw everyone in jail for the most minor infraction" crowd into the building.