There are roughly 3055000 diagnosed people for 211000 deaths.

Your math is right, and I wondered about the same thing one month ago when France went on lockdown.

First, there's a measuring bias, all countries measure different things, Germany, for example had chosen to pay great attention to only declare deads that were diagnosed from a positive covid test, but if a positive covid patient dies from a cardiac arrest they're not counting it. On the other hand they're performing over 50000 tests per day, allowing them to deal and follow the mildest cases and at the same time mechanically lowering their death/infected ratio... Other countries have swollen covid figures due to broad attribution (no more pneumonia, no more winter flu, only covid...) That mixed with the lack of global testing make figures inaccurate. You can't really extrapolate from such few numbers, and when you do 27% of new yorkers should've been infected now.

We're facing a complex problem here, this is an unknown pathogen, and those are quite rare, well, there's one every 10 years, but this one was spreading really quick and hit hard places with already shredded medical systems with a lot of old people, so figures were bad. Another issue is media and social media pressure... The day before the lockdown here, one litterally could smell fear, people were scared by multiple sources reporting multiple things tending towards something really big.

And this is just a theory... But when you're leading a country, no matter the issue, your end goal is to avoid being part of history in a bad way. I guess, and they all mentioned it, the biggest fear of our leaders was overcrowded medical system, with sick personnel, entering a war triage kind of selection. We know one things about pathogens from ebola and lhassa fever outbreaks: trained professionals, with efficient ppg and really precise standards usually still end up getting those in higher proportions than the public... And of course the mask mystery, since h1n1 we are producing outstanding amounts of masks, and States have huge stocks, not talking about the huge stocks of chemical gas masks that are even more efficient as blocking eyes, which are a proven channel of infection for covid? I mean, our countries have invested massive amounts of money after 9/11 and h1n1 in masks, the latest French report on chemical risk mentions 10milion of masks and 54milions of cartridges... And of course the delays, both Europe and USA seems to have reacted after big events that could've spread it more broadly (like spring break or French local elections....) So, amongst other theories, I wouldn't be surprised to learn that our leaders, flattened the curve with a specific goal in mind : infecting and immunising frontline workers, while the medical system could handle the worst cases amongst them, sheltering everyone else to get them out of the equation... That would allow a slow reopening to spread the disease in a controlled way, managing the cases as they show up.

That's just a theory, but I prefer one simple theory encompassing all the things that are explained in complex manners in any case.

Tbh I have no clue, maybe one day we'll learn the real reasons, but that will take years, all we have now are theories to keep us busy under lockdown, I like this one today, I might have another one tomorrow, who knows....