Calling, while cheap, isn’t free or infinitely fast. They’d likely pay for knowing “active” or “lucrative” numbers.

Jim Browning videos are a fantastic resource to learn more about the inner workings of scams https://youtube.com/c/JimBrowning

Calling isn't zero cost, and that spammer time isn't zero cost, so in this case, there is a incentive from the spammer to weed out people who costs the most.

So isn't the popular idea that you should NOT answer spam calls wrong? Logically, you should answer every spam call and try to get them to stay on the line for as long as possible, therefore maximizing their cost.

This is assuming they have some CMS software on the backend that allows them to categorize numbers.

>Logically, you should answer every spam call and try to get them to stay on the line for as long as possible, therefore maximizing their cost.

You also have to factor in your costs as well. I checked a random VOIP service and they charge a penny per minute, or $0.60 per hour. The federal minimum wage is an order of magnitude higher at $7.25/hour. Therefore it's more expensive for you to stay on the line to mess with them.

There are systems to waste telemarketer time, ex lenny troll [0] (which acts like a senile person). While I used to answer in bad faith, I stopped given the realization that I am hurting people of lower economic standing more than the company that employs them.

[0] https://lennytroll.com/about.php

On the tangential topic of war dialing (calling every number as an exploration) I recommend checking this discussion https://news.ycombinator.com/item?id=27602383

They can and do, but it's cheaper if they have a list so they can just text numbers they know get SMS.