There is nothing simpler, except that some very well-funded special interest groups never want to see this happen.
When I was on a limited plan, the amount of spam messages and calls were virtually zero because the limit would run up and be charged against the caller (internationally).
The month I switched to an unlimited, I started getting spammed.
Now much of the spam is domestic, but I fail to see how this is possibly unfeasible technically.
And what well-funded SIGs are our to get your phone call tax plan?
By way of indirect response, Bernard J. Stern's "Resistances to the Adoption of Technological Innovations" (1937):
https://archive.org/details/technologicaltre1937unitrich/pag...
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