The libertarian Cato Institute has a webpage that succinctly describes the political reasons why conservatives are so opposed to heatlh care reform: Blocking Obama's Health Plan is Key to the GOP's Survival.
In short, a successful government-run health care system would draw people to the Democratic Party, because people would be dependent on government (and on Democratic politicians) for an essential service.
Of course, we already do depend on government for police, fire, roads, education, and numerous other services. Conservatives hate this and want to turn back the clock. They don't like it when government works, because it goes against their ideology, even when government is more effective and cheaper than the private option -- as it is with health care in most industrialized nations.
So, conservatives and their corporate backers are pulling out all the stops in their effort to torpedo health care reform. Even though up to 3/4 of Americans support a strong public option, and even though government-run health care would give better coverage at much lower costs, we might not get it, unless people demand it -- unless Americans organize to oppose the corrupt system.