Edit: actually the more I think about your comment, the less sense it makes. What information could be gained by an anonymous phone call? Please walk me through this scenario, because I don't see it at all. Who is giving away sensitive information to an anonymous caller that they wouldn't give if there was caller ID?
My doctor's office won't leave messages, and appears to have about 20 minutes a day where they pick up the phone, so, if I don't pick up when they call, then I can't talk to them. (I know, I know, get a new doctor. But this is my third try to find a specialist who's willing to go beyond "here are some easy suggestions that you've already told me don't apply to you," and there are only so many battles that I can pick before I just run out of specialists entirely.)
To reiterate, calls need to say who's calling. They don't need to come from a number that will be answered.
It's about liability, and making sure there are consequences for spamming.
Google your name and you’ll likely find much more information than the white pages ever had. I found an old email address of mine from the 90s that is long gone, every place I’ve ever lived, relationships to various family members, my parent’s address dating back decades, even my grandfathers last couple addresses and he’s been dead for over 20 years.
About 10 years ago someone on eBay tried to pull something on me and I was trying to figure out what I was dealing with. Within 45 minutes I had his name, parent’s names, phone number, and their address. I didn’t do anything with it, but it wasn’t that hard to find, with nothing more than a username or email address.
The example given was child support, which is financial, not visitation. I’m assuming this person would be an ex-husband, and that abuse, leading to assurance that he can’t track you down, means visitation with the kid is off the table.
And anonymity against your interlocutor is usually a very bad thing. Even though there are a few exceptions.
But.. there is money on the line. Clearly, money from telemarketers/scammers/whoever is using this tech is enough to make telecoms hesitate from actually doing something about it.