Miracles

The per capita death toll in the US, relative to other countries, is embarrassingly high, though given everything, it's somewhat miraculous it  hasn't been much, much higher. Getting vaccines early and having a decent enough vaccination rate for the elderly helped. 

 The "interesting" thing is that the number of cases never exploded quite as much as they might have, relative to other countries, through the various waves. Some of that is probably due to differences in testing rates, but not all!

Have my own theories, but don't know!