In some countries it's illegal for companies to call random people, they need to gather opt-ins from all people they wanna call.
Customers complain to carriers, who then either get the offending voip provider to block the scamming customer, or just threaten FCC action. But the whole cycle is so slow and you're fighting a never-ending shapeless horde.
I think STIR/SHAKEN will help with this if it ever gets fully implemented and enforced, and voip providers are always trying to come up with better fraud detection to avoid the man-hours associated with assuaging carrier concerns, blocking the customers, etc, etc.
1. Spin up new voip company
2. Issue death threat to US President (or similarly powerful man)
3. Spin down voip company
4. Wait to see if/when someone finds out who you are