How do you explain Korean data with this hypothesis ?
As of March 30, for 410k tests, they detected 9789 cases. They are testing more than 10k people everyday since late February, never got more than a thousand cases on one day and this is biased by contact tracing.
I read the Covid 19 vs Influenza blog post and age mortality from the korean CDC is closer to 10x flu than classic flu.
Overall, Korea is evidence for "low infectiousness, high infection fatality rate". The fact that containment works in some countries seems to be evidence too.