Americans have a traditional distrust of the government, so many don't want a government run system.
More socialized systems seem to work well for minor care, but fail when it comes to major procedures. I know many Canadians and British that come to the US for medical procedures, because they are on a waiting list back home.
I pay $86/month for my health insurance (I'm responsible for the first $4K of medical expenses each year) and have always been able to see my doctor within 24 hours. The same can not be said for government services. I can't even get the government to consistently recognize my marriage or correctly deliver my mail.
And I've never heard anyone say that they would rather go to the government run Veterans Administration hospitals than to the Mayo Clinic.
As a Canadian I disagree. I had a major procedure few years ago and waited less than 24 hours. It wasn't an emergency either. On the other hand, my sister's neighbor in Wisconsin died from undiagnosed heart disease. She had no insurance because she had a pre-existing condition involving her bowel. (I don't know all the details). At least your new health care bill starts to address some of the unfairness in the US system.
As to why the US doesn't have socialized medical in this day and age. I think there is just too much money to be made by the powerful players. It could be done if there was a will for it. There are so many social models in the world now, that they should be able to design a very good and efficient and fair public system by doing an analysis of what works, what doesn't and applying the lessons learned by other countries to their own local situation. I think a mixed system could be designed that would address most of the problems they currently have.
But politics in the USA now only happens through a very narrow left-right lens. Actually, a centre-right lens... The whole public discourse is conducted around this Democrat/Republican quest for power and service to their corporate masters. Masters who are for the most part the same guys, who really only want what's best for their short-term bottom line. Not what is in their or the public's best long term interest.
So the public gets fed a line about "free markets", "socialism" and the evils of "big government". Yet all the while, those same guys are the ones who don't mind "big government" when it comes to defense spending, interstate highways, subsidies to airlines and railroads, spending on the power grid, bailing out banks and the failed auto industry. The list is long of companies that benefit from govt contracts and the profits are huge. But when it comes to something that might give a tangible benefit to the taxpayers, the corporate stooges in Congress and the media start running around with their hair on fire screaming about death panels, socialism, "Obamacare" and the fatal threat this poses to the American Way of Life.
And the poorly educated, badly informed, but well entertained American public believes the lies they are told. That is if they stop "consuming" long enough to look up from their bowl of Coco Puffs and check out a news channel.