>Because the US does not write off senior citizens because they are so old that the money spent on the procedure is not worth the time that they have left.
>
>A cynic might respond that the US writes off 45 million working age people instead. ;-)
>
>But to address your point: for this to cause higher cost it must mean that less expensive first-world countries do write off the elderly in this fashion. So for the purposes of discussion: is there a difference between "postponing death" and "prolonging life?"

“Of people currently classified as uninsured, a conservative estimate says about 45 percent of them would be able to get health insurance right now if they wanted it,” says economist Glen Whitman.

Other sources:

It turns out that 253.4 million Americans -- or a whopping 83% of the country -- have health insurance, whether it's through private insurers, employer-based coverage, a government program or Medicaid/Medicare. The majority, 202 million of the 253.4 million, pay for private insurance.

And as a number of clever skeptics have recently pointed out, breaking down the 45 million number reveals that far fewer folks are actually uninsured. Nearly 10 million of those 45 million aren't even American citizens, and nearly 17 million of them can easily afford insurance, but choose not to get it (these folks will be taxed under Obamacare for opting out.) When the numbers are crunched, it turns out that only 11 million legal American citizens who would like health insurance don't have it, and even that figure is likely high. If we take it at 11 million, that's less than 4% of the country

I'd be more likely to believe this (with alittle bit of inaccuracy due to under-reporting):

http://www.census.gov/prod/2008pubs/p60-235.pdf