FFS USA, not every problem is a problem to solve by "the free market". You can see the America-Is-Great Mindset in a lot of these comments: Even the US has a problem with robocalls, so that must mean it's an unsolved problem obviously. So we have to solve it with our superior technology!! Just no. Almost nobody else in the western world has this problem. How? Regulation. In Germany, if you get reported for unsolicite…
Effectively, a call to a mobile phone costs at least about 0.01 EUR per minute. This puts a lower bound on the cost per robocall.
I wonder how much of the difference in the number of robocalls simply comes down to economics rather than to efficiency of regulators and legal frameworks.