In 1999, health administration costs totaled at least $294.3 billion in the United States, or $1,059 per capita, as compared with $307 per capita in Canada. After exclusions, administration accounted for 31.0 percent of health care expenditures in the United States and 16.7 percent of health care expenditures in Canada.

Okay, so taking that at face value the US spent $731 per capita after overheads are deducted, while Canada spent $256. I believe this more than demonstrates the accuracy of my assertion. There are a lot of differences between the US and Canada, but the bulk of the difference is not explainable by overheads, and if we had a magic wand that could somehow instantly give the US system the same overheads as the Canadian system, it would still be screwed.

(Also, it's not obvious we should take that at face value. Calculating overheads and making sense of the resulting numbers is a famously difficult task. For example: It's easy to cut overhead by simply abandoning any effort to control costs, fraud, misuse, or ensure you're funding the most effective treatments, which means you need to dig deeper and figure out why a system has the overhead it does. Overhead is not automatically wasteful. In addition, there's an ongoing debate about the correct denominator to use in these calculations. The Canadian system covers basically everyone in Canada, but in the US the elderly, who use a disproportionately high amount of health care resources, are mostly on Medicare. If you calculate overhead per patient, rather than per dollar of spending, the oft-criticized private system in the US has lower overhead than the oft-lauded Medicare system. And so on. Which isn't to say that overhead isn't truly lower in Canada than the US; as far as I know it is. But the gap you cite is probably an upper bound for the effective size of the overhead gap, and it's still small compared to the spending gap.)