It's been a while since I crunched the numbers-back when france had 40 or so cases. What is going on in Italy is definitely concerning. Part of their problem includes a shortage of ventilators and refusal to treat the elderly. I am not sure that Italy should be used as a model of what should be expected, but nonetheless a model of what can happen if a nation isn't prepared. We were in the impeachment proceedings when Corona started firing up in China, so the USA is a bit late in the dialog about preparedness-but the oceans did provide some useful time delays. As bad as Italy is (about 7.7% death rate) , South korea has about 8300 confirmed cases but only 81 deaths-Just barely below 1%. As bad as Corona is in italy, the number of deaths (2,158) is still a fraction of those killed by the flu per year. see https://www.sciencedirect.com/science/article/pii/S1201971219303285 showing 7k-25k/year). Granted the Corona outbreak likely hasn't peaked in italy yet and the death toll is still climbing by hundreds a day, there isn't yet grounds to say it is worse than an ordinary flu-unless you are unfortunate enough to catch it. But it has the potential to be on par with or worse the the ordinary flu there.

I am also skeptical of high outbreak estimates followed by high death numbers. It is possible a majority of the cases are asymptomatic and not being tested. Some scientist have suggested the number of asymptomatic cases may be 6x the number of confirmed cases. Which is about the ratio between Italy and south Korea in terms of CFR. Whether or not screening specifically caused this ratio, I do not know. While examples of unreported asymptomatic cases supports arguments for a higher infection rate [which will probably never be counted into official records], it also undermines high death estimates. Meanwhile in some places like the USA where even people with symptoms may not be tested making the infection rates look lower, but the mortality rate will look higher....and then you have places like Italy who don't have the ability too and refuses to treat the most vulnerable driving up the death rates. How a country screens [and treats] corona patients will affect the perceived death rates (CFR) greatly. Unless someone digs into details about how a country is screening, It might create windows broad window of what to expect but will not provide scientific certainly-and even that could be skewed through quarantine [and treatment, and border control] efforts.

I am not sure how well South Korea and Italy Screen their people. Full Screening not only captures a clearer picture, but could lead to more efficient quarantine procedures-which may cause temporary fixes. But full screening [as well as quarantine] also poses substantial violations of civil liberties.
China, Italy, and Singapore have about peaked in terms of outbreak. China, who had quarantined, is opening its factories again-and doesn't yet appear to have a secondary outbreak. If the peaking is through herd immunity, rather than mere quarentine, it suggest some expectation [subject to screening policies] of what percent of a population can be expected to become infected-only China can't really b trusted. Italy and South Korea have about similar sized populations, but Italy has over 3x the infections of South Korea. So South Korea isn't a good expected estimate on the overall infection rate on a country, Italy could be a better model of creating an expected infection ratio than Korea, but they are still doing mandatory quarantines making a true estimate difficult.

Places like San Francisco who gone crazy with Quarantine may find out in the long term their efforts did nothing except create a time delay, and when the rest of the world has about peaked they could get nuked by Corona and might choose quarentine again and hope this time when it has ended Corona is extinct. Self quarantine is good as risk adverse people can wait it out until herd immunity is built in a population. but mandating the quarantine of healthy people is kind of, but not entirely, stupid if you haven't contained all the infected people too. If South Korea peaked because of Quarantines and travel restrictions, then they could get hit hard again the moment they open their border. Not saying they will, but the potential exists.

Also I'm not saying mandatory Quarantine of healthy people is a bad strategy in itself. If it slows down or stops the disease locally in the short term, then there is greater herd immunity when it is over-perhaps enough to stop it. But if that is done when it first reaches, or even before it reaches, a municipality where such a quarantine hasn't fully contained the outbreak, then that herd immunity, if any, is de minimus and a secondary outbreak can be expected.