Recent Revelation: Healthcare Monopsony Buying Power

Many single-payer (nationally funded) healthcare systems pay a lot less for drugs, services, and equipment than US insurers do. They have a monopsony and therefore a lot of buying power--makes sense, right? Erik recently has a revelation that calls this logic into question... though without any clear answers.

Sources

In this case Wikipedia for each country’s size and the biggest healthcare providers in the US.

Of note: https://en.wikipedia.org/wiki/List_of_countries_by_total_health_expenditure_per_capita