Historically, centralised copper circuit-switched technology charged for use in relation to the distance between conversation end points and the duration of each voice call.

Packet switching, enabled by current commodity digitisation hardware, makes the distance cost factor irrelevant, much as the Penny Post did for snail mail.

That leaves, beyond some fixed access charge to cover OPEX costs, the matter of duration of “the call”.

One way to consider the above is to think of duration as exclusive access overhead – usage of the network resource that denies or at least degrades (aka service contention) the experience of other network consumers for the duration of such usage;

Think of a parallel with early main-frame computers where each user consumed scarce processor time vs a CPU (single/dual/quad core) per user today.

Time taken x bandwidth consumed

Different forms of communication require different sizes of dedicated data pipes in order to deliver the desired interaction in real time -

text chat << voice call << video conference << healthcare telepresence

To refine the definition of exclusivity:

Time taken for conversation x (bandwidth/second required)/minimum end-to-end bandwidth available

Given first mile FttH, mid mile and global fibre connectivity – a virtual optical local-global conversation pathway – distance-independent, on-demand songlines really ….

and > 1TB/second bandwidth capability of half-decent quality mono-mode fibre today ….

Well, sounds to me like the end of artificial bandwidth scarcity ie. all calls will be free.

Note the contrast with mobile network operations where a cartel exists on account of licence fees paid for exclusive access to radio spectrum… hence the vital importance of first mile infrastructure ownership.