This seems like a problem with misaligned incentives. The profit from scammers successfully deceiving people is higher than the operational cost of cycling through phone lines, labor costs, etc. Is there something we can collectively do to change these incentives? How about individual efforts? Or is this a technological arms race? Are there other countries that have solved this problem?
That should take care of most spam/scam calls, as it requires the telecoms to verify that the callerID data matches the source of the call.
This won't eliminate such calls, but it will make it much harder for spammers/scammers to run their robocalling projects effectively.
One of the issues we have in the US is that telecoms charge the recipient for these calls, not the originator. In some (many? most?) other countries that's reversed and such activities are much less prevalent.
I imagine that once STIR/SHAKEN is fully implemented, a variety of actors will step in to capitalize on the opportunity to provide blocking/tagging spam/scam calls as well.
As with most things, there isn't a simple, singular solution.
This RoboCash app does exactly that, and it pays you for each call you block as an added bonus. [2]
STIR/SHAKEN is a partial solution that doesn't go far enough to solve the problem.
[1] https://drive.google.com/file/d/1c1GyiVVZFDiUuxWkBCQ63qLdJgP...
[2] https://play.google.com/store/apps/details?id=com.fyncom.rob...
Disclaimer: I made the app and wrote the white paper.