The point isn't that we use hospital admissions as a metric to infer cases or some other metric, it IS the metric that matters. The problem over the last year wasn't that there exists a person who is at risk, it's that there didn't exist any healthcare system capacity to treat them.

From very early on in the pandemic, it seemed to me like our goal for optimal balance between caution/risk was to try and maintain the highest level of hospital occupancy that is sustainable. If every single person quarantines perfectly, then our hospitals are empty, but so is every business. If no one quarantines, our businesses are full, but so are hospitals and everyone's viral load; i.e. maximum mortality.

With the vaccines now available, it seems like our goal should still be be to maintain the highest level of sustainable medical system occupancy.