While this is a very nice simulation and explanation it has a serious flaw: It assumes a fixed CFR, IFR, and hospitalisation rate. This doesn't seem to be case as evidenced by the large differences between the countries with different response curves.

The inability to change the parameters is a major problem with the simulation and invalidates a number of conclusions at the end.

What we can observe so far is that CFR is heavily skewed towards the old and frail with significant co-morbidities. Most likely there is another, not yet fully identified, medical cofactor that makes this virus particularly difficult for a very small number of people of any age. Outside of those groups the virus doesn't seem to be very symptomatic for the majority of infected people. Note that symptomatic in the medical sense and common usage is not the same. The latter having a way higher subjective threshold.

The simulation should also account for the "weak tree" effect in that the majority of the susceptible will succumb to it on the first contact. In the following years the number of susceptible will be much lower and only go up with the remaining people going into ill health and becoming susceptible, if they haven't developed any immunity from the previous encounters.

A simulation to draw real conclusions from must have an adjustable IFR, CFR, the corresponding hospitalisation rates, and the age and health distribution of the population for a region to be modelled.