Gallup has found in polls for a decade now that two-thirds believe the government should guarantee care for every American: they are as good and decent and concerned for each other as any European. No: it is because private insurance companies make a fortune today out of a system that doesn't cover the profit-less poor, and can turn away the sickest people as "uninsurable". So they pay for politicians to keep the system broken. They fund the election campaigns of politicians on both sides of the aisle and employ an army of lobbyists, and for their part those politicians veto any system that doesn't serve their paymasters.
Look for example at Joe Lieberman, the former Democratic candidate for Vice-President. He has taken $448,066 in campaign contributions from private healthcare companies while his wife raked in $2m as one of their chief lobbyists, and he has blocked any attempt in the Senate to break the stranglehold of the health insurance companies and broaden coverage.
The US political system now operates within a corporate cage. If you want to run for office, you have to take corporate cash – and so you have to serve corporate interests. Corporations are often blatant in their corruption: it's not unusual for them to give to both competing candidates in a Senate race, to ensure all sides are indebted to them. It has reached the point that lobbyists now often write the country's laws. Not metaphorically; literally. The former Republican congressman Walter Jones spoke out in disgust in 2006 when he found that drug company lobbyists were actually authoring the words of the Medicare prescription bill, and puppet-politicians were simply nodding it through.