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