It’s still being deployed. Or more precisely, it’s now mandatory and the service providers which haven’t implemented it are in the process of being forcibly removed from the PSTN: https://natlawreview.com/article/fcc-cracks-down-are-you-rea...

The US telecoms industry has supposedly been "fighting phone spam" for well over a decade. I can tell you it's simply not working.

The system will die, if not from the abuse than from rejection by individuals, businesses, and organisations. And I suspect we'll never again have a single universally-accessible voice comms system again.

Email has similarly been slowly dying for similar reasons.