It's not defaming the OP. I did address the merit of what they said.
> If it takes 2,000 calls to find one victim, and you're paying 10 cents per call, you'll spend $200 per victim.
Yes, but in reality it takes less than 10 calls to find one victim.
> Will you make that much back, and will it be enough to offset all of the other costs involved in trolling?
These scammers are pulling hundreds of thousands from individual victims. Even at the low end they're earning thousands.
These scams are so profitable that you can't increase costs of calling enough to stop them while also keeping phone calls accessible to normal people.