Like many things in economics, it's imperfect.
If you compare the US with Canada, which has a similar mixed ethnicity, the dollars to life expectancy is still way better in Canada.
To save some time, I think the typical libertarian argument is to admit the system in the US actually does stink in terms of costs, and argue that if only we had a truly free market, where people could instruct their ambulance drivers to drive around shopping for the best price/performance ratio for their emergency surgery, then things would be better in the US.
This just goes around and around and around, though, doesn't it. I somehow suspect we won't see "health care economics problems solved on niche web site" as tomorrow's headlines.
I love to talk about this stuff with people in person, but the bandwidth of a web site is just too low - people write books on these subjects, for pete's sake.