The problem here isn't with the mortality per se, it's with the strain on healthcare resources. We just don't have the capacity to deal with an influx of cases requiring hospitalization. Currently about 10%+ of COVID-19 require that. We don't have the beds, the oxygen support, the ventilators, and generally the ability to keep these people from infecting others. That leads to scenes like in Wuhan where people get turned away from hospitals, where they end up dying at home, where bodies require mass cremation, etc. This could happen anywhere. The US healthcare system is not prepared for this. (I don't believe for a second in the assertion that it's the best in the world. Perhaps quality of care is good, but the system that pays for it is a joke. But it's also hugely variable, with some great hospitals attached to university research centers, and a ton of terrible underfunded ones.)