Ars Technica:

Years into the robocalling frenzy, your phone probably still rings off the hook with “important information about your account,” updates from the “Chinese embassy,” and every bogus sweepstakes offer imaginable. That’s despite promises from the telecom industry and the US government that solutions would be coming. Much like the firehose of spam that made email almost unusable in the late 1990s, robocalls have made people in the US wary of picking up their cell phones and landlines. In fact, email spam offers a useful analogy: a scourge that probably can’t be eliminated but can be effectively managed.

Finding the right tools for that job remains a challenge.

That headline is painful but likely true. It also means my iPhone is much less useful as a phone than it would be if this issue could be solved. I never answer my phone any more from any unknown-to-me callers.