I once read that businesses that have phones that will supply ID to callers get a fraction of a cent per call from the phone company. If they can auto-call enough people, they can harvest noticable cash even if they never talk to anyone. Hiring people to talk would be an unnecessary expense.
Not that I have any clue what the actual costs and benefits would be - or even if anyone is actually doing this.
In the U.S., we’ve had the Do Not Call Registry since 2003. And, when it was first enacted, and we signed up on it, our level of junk phone calls dropped to nearly zero.
But, in the past 2 years or so, it’s skyrocketed again. I’d guess we get 3-5 junk calls on our land line each day, and I get at least that many on my cell phone, too. I’m going to guess that the calls are largely coming from outside of the U.S., where the existence of the U.S. law is irrelevant.