There is too much we do not know about this virus. There is a strong suspicion that there are many cases of mild infections that are going unreported. That children are not showing up in the statistics in a flu-like pattern is just weird. While pre-existing heart disease and immune suppression increase morbidity is understandable; that pre-existing conditions of the lungs such as COPD are not much of a factor is also weird.
There is a possibility that large numbers of mild, undiagnosed, cases are conferring some degree of immunity to the Chinese population, and this may be limiting further expansion of their epidemic. Cow pox was a mild disease that conferred immunity to small pox; it could be that some mild and common childhood disease is protective against covid-19. That China appears to be past the peak of the disease is not unreasonable.
On a different aspect: The numbers game.
We have been seeing numerous reports of numbers of dead as a small percentage of numbers of active cases, and numerous suggestions that covid-19 has a mortality rate of maybe 1% or maybe 3%, which doesn't sound very bad. However this is probably the wrong statistic to use, at least at this time while the pandemic is spreading so rapidly. John Hopkins and others report that the interval between diagnosis and death is usually somewhere between 7 and 14 days. That means a mortality percentage based on currently reported active cases is including a large number of persons who are in the early stages of the disease process, before death is much of a possibility. A more useful percentage is the percentage of mortalities of "finished cases", where a final case is one that has ended either in recovery or in death. We now have enough data to calculate the final mortalities.
John Hopkins has been tracking the needed statistics and they are being reported on a number of web sites, including https://www.worldometers.info/coronavirus/ where I found the following:
For March 13, 2020 at 15:12 GMT:
. . 1. Total number of cases: 139,578
. . 2. Number of deaths: 5,120
. . 3. Number of recoveries: 70,733
. . 4. Therefore, number of final cases: 75,853 (recoveries plus deaths)
. . 5. Mortality rate: 6.7% (deaths as percentage of final cases)
I've run this algorithm on reports for the world and for several European nations each day for the last five days. With the exception of Italy, the mortality rates have been between 5.5% and 6.5% every time. My impression is that this has been gradually increasing and as a WAG it will stabilize around 7%. Italy is a major outlier at more than 40%, possibly because Italy is using more stringent criteria for recovery status and under-reporting relative to other nations, or because their much older population is very much more susceptible, or probably some combination of those and other factors.
I am not bothering to track the USA since its response to covid-19 is so badly broken there can be no confidence in the numbers the USA is reporting.