This is great. People need to be careful about inferring certain details from headline numbers. I think hospitals are also incentivized to test and label patient Covid if they can, since they'll be reimbursed more. In any case, it seems like the reason fatality rate is decreasing is that at-risk people (i.e. old, obese, respiratory issues, etc) are taking more precautions and being smart. The young continue to be stupid.
Under 30, driving on the highway is more likely to result in mortality than covid is. Risk adjusted, cocooning strategy is actually safer than quarantine, because quarantine forces multi-generational households. E.g. Opening universities leads to safer outcomes on balance than closing them.