Re: Give the carriers (phone companies) a piece of the fines...
If they can't be identified for billing, then their calls don't get connected. No corporate entity does free work (counting tax deductions, "good will" advertising, and "brand-name recognition" as having monetary value - a corporate accountant can give you dollar figures for each). Hell, they try not to do work unless they can get paid 2+ times for it; even if it's not work, they still won't do it for free.
Lets say, for a worst-case example, Scams 'R' Us, based out of Russia, uses a dodgy VOIP provider to connect to Tata Docomo in India, which routes the call through Bouygues in France, who directs the call to Verizon in the US. Verizon bills Bouygues, who bills Tata, who bills the VOIP provider, who bills SRU (possibly as part of their subscription). Bouygues may not tell Verizon where the call originated, but they sure as hell know who to charge. If most of the calls coming into Verizon from Bouygues are scam/nuisance/robocalls, then Verizon could tell them to clean up who they accept calls from, or
their rates will increase they will stop connecting those calls. Bouygues tells Tata the same, Tata may well drop the dodgy VOIP provider, or bill them extra, which would raise the price of Scams 'R' Us's subscription, possibly making them uneconomical as a scammer.
To restate: If they can be identified for billing, they can be identified for blocking.