I read the study and nowhere does it mention when or how ventilators were applied.

If ventilators are a scarce resource/bottleneck and ventilation is applied by prioritisation then I could see the mortality rate skewing up as a function of treatment being applied too late.

It is worth bearing in mind the mortality rate of non-swamped health care systems.

For every NYC/Paris/Lombardy/Wuhan there is a South Korea/Taiwan/Hong Kong with very different data profiles.

I would love to see the mortality rate for ventilation support in these countries/cities...