It's based on an assumption that most people do not report being sick and aren't tested. In this situation where vast majority of people are aware of Coronaviru

It's based on an assumption that most people do not report being sick and aren't tested. In this situation where vast majority of people are aware of Coronavirus I doubt this is true. Diamond princess case is an interesting one, but it is also highly quarantined ship where they stopped the spread early on and then gave huge amount of medical attention to people on board. Even in such a situation, there were 10 deaths and apparently 30 or so people are in serious condition. Let's say half of those die, so we get to 25 deaths of 700 infected. We get 3.5%. One more issue is that apparently testing is not adequate, there have been numerous cases where someone tested negative several times only to test positive after a while. This means that containment processes in the western world will not work, no one is willing to blockade a huge region like China did. In the end, we could end up in a situation where China understood the issue and acted decisively to stop the spread while the western world does half measures and ends up having a huge pandemic on their hands.