Pai did try to push companies to adopt authenticated calls voluntarily. His hand was forced by congress later on https://arstechnica.com/tech-policy/2020/04/aji

Pai did try to push companies to adopt authenticated calls voluntarily. His hand was forced by congress later on https://arstechnica.com/tech-policy/2020/04/ajit-pai-follows-congress-instructions-requires-new-anti-robocall-tech/ https://arstechnica.com/tech-policy/2020/04/ajit-pai-follows... I guess in theory at some point this year everyone will have gotten on board by the deadline and the telcos can start providing more technical options to stomp out the calls.