The PSTN is simply not sustainable. It’s a relic of a time when there was no practical way to authenticate or validate calls. Today, with malicious actors able to dial in from anywhere in the world at negligible cost, the system is fundamentally unequipped to handle the abuse it faces.
Efforts like STIR/SHAKEN exist, but they’re little more than a band-aid—and not a particularly effective one—because the underlying network was never designed with resilience or trust in mind.
I know some people push back on this view, often pointing to edge cases where PSTN’s ubiquity still provides value. But as trust in the system erodes, so does its relevance. And if the majority of people already avoid answering calls from numbers they don’t recognize, its practical utility is clearly diminished.
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