WiFi / pure-VOIP based calling should be able to disambiguate between the network and the messaging layers. This means that a given cellular modem wouldn't be traceable to a specific contact, or call history. The modems could be swapped amongst individuals readily.

This is similar to the situation that already exists for PSTN voice comms currently: Whatsapp, Signal, Jitsi, or similar voice- or video-messaging systems. They'll run over an arbitrary network, through VPNs, etc.

Mind, the major comms-apps/social networks might have their own ID requirements forced on them, but there's far less a capability to keep people from defecting from these.

I continue to think that global PSTN networks are pretty close to general collapse, given spam, robocalls, harassment, tracking, and similar forms of abuse. Millennials & GenZ are already notorious for their reluctance to make or take phone calls.

<https://theconversation.com/young-people-hate-making-phone-c...>