> because our understanding of the situation was very poor (how wide spread the virus actually is).
It's estimated that there is at least a scale of 10x unknown infected vs known infected. South Korea, Taiwan and Singapore have only been able to stay nearly CV-free because they have extremely strict testing regimens - while the US has almost no testing capacity at all (and many have to ignore a positive test as they need to work to survive/keep health insurance), and Europe doesn't fare that much better to be honest.
No nation has done mass randomized testing to see how much of their population has had the virus. If China did it, they haven't released the results of that test.
South Korea will not be able to remain quasi Covid free, unless they plan to never open their borders up ever again. The rest of the world is going to be flooded with the virus and the disease. The bulk of the populations in the EU and the US will likely get the virus, and as you note, fortunately, the death rate hopefully maybe plausibly is 1/10th or 1/20th what we think it is due to the volume of unknown cases roaming about.
The only way SK remains mostly free of Covid, is if the virus goes away and doesn't come back next year (and or we get a vaccine they can use next year). SK can hold in place, while the US and EU and other regions (China already) likely go back to work; then as it fades elsewhere with increasing herd immunity, SK can come out of their protective shell. Otherwise they'll have to remain in perma lockdown, perma quarantine, perma heightened mode.
It's estimated that there is at least a scale of 10x unknown infected vs known infected. South Korea, Taiwan and Singapore have only been able to stay nearly CV-free because they have extremely strict testing regimens - while the US has almost no testing capacity at all (and many have to ignore a positive test as they need to work to survive/keep health insurance), and Europe doesn't fare that much better to be honest.