They are actually pretty good at driving the prices down to something reasonable in most cases. While the headline prices are absurd, the prices actually paid by public and private insurers, whether Medicare or Blue Cross or Aetna, are much more reasonable. Not as reasonable as in much of the rest of the developed world, but the gap is not as gigantic as it initially seems.
The really big gap between the U.S. and the rest of the developed world on medical costs isn't the cost of individual procedures (once you've taken into account what insurers actually pay), but the much larger amount the U.S. spends on last-6-months-of-life "heroic care". If that were brought more in line with international norms, the overall cost-per-person numbers would be much better.
If I get table 4 right, people who manage to live past 85 years will have 1/3 of their health care spending after their 85th birthday (not entirely accurate, but a reasonable simplification).
The really big gap between the U.S. and the rest of the developed world on medical costs isn't the cost of individual procedures (once you've taken into account what insurers actually pay), but the much larger amount the U.S. spends on last-6-months-of-life "heroic care". If that were brought more in line with international norms, the overall cost-per-person numbers would be much better.