The hope is that it results in some self-reflection for the caller, though it hasn't reduced the number of calls.
I'd be curious to hear how your approach works out. Ultimate best scenario would be to get completely removed from their lists - but I've almost given up hope on talking sense, and my provider, leaving Fire versus Fire.
I don't think there is any action a consumer can take to reduce the number of calls or get removed from a company's lists. There is no incentive for the company and the person who calls is as much a victim of capitalism in that moment as you are. Just two people wasting each other's time as a result of the operation of a corporate machine.