I think 5 cents per call attempted would cut down on this a lot. The scammers do appear to vary their behavior according to small economic incentives.
Answering one of these phone calls increases phone activity. Wasting their time appears to reduce it. Anecdotally, one guy on Reddit stopped calls by telling the Microsoft scammers that he had a Linux machine. I’ve stopped daily calls (at least for the past week or so) by (unconsciously) simulating Jolly Roger Telephone and keeping the person on the phone as long as I could (about a minute). I cost them less than a nickel (assuming $2/hr wages) but that was enough to stop the nonsense. So far.
There is legislation to crack down on Caller ID spoofing, but deadlines have come and gone and the problem seems to remain. STIR/SHAKEN was suppose to go into force in 2021, but I can’t find a good update on this federally mandated technology.