> Since the US has by far the sickest human population on Earth (it's not even debatable), I guess the current system has been a spectacular failure

I suspect everyone affected by the sub-Saharan AIDS epidemic would disagree very strongly, even despite the improvements over the last 20 years.

More generally, the US may be an outlier among industrialised nations, but the floor for health in general is much lower than the USA.

This also means you have a long way further to fall if you allow incompetent leadership.