I'm so grateful for this website. The voicemail I got claimed to be the IRS calling me. It was very clear that I should call them back, repeating their number twice. I've deleted the message now, so I can't check what else they said.
Your suggestion is terrible. Why would someone want to engage in conversation with a scammer, which surely lead to more calls, not only from them, but other scammers. Then, you will complain about "why is the government not doing anything about these calls?"