Do you see what the problem becomes? The problem becomes what do we want to cover and for how long. The answer depends on the amount of resources you want to devote to that issue. We could cover every medical condition for everyone forever until they die. Do we want to pay that amount of money as a society? What are the other implications of developing that kind of system? What abuses will occur? When you start taking other people's money to do something for yourself, you will find that other people have other priorities. Maybe they prefer to save their money for retirement. Maybe they prefer to use that money to provide their kids an education instead of healthcare. Maybe they want to buy a nicer car instead. Who knows?
The problem you have is that we as a society don't agree on what the best use of our money is yet. Clearly we agree it was wasted on this website so far. What other waste are we going to find? If we find too much problems with the system, we don't have an easy out when its run by the government. When it is run privately, we can take our money somewhere else. Don't like this hospital? There is another one down the road. Don't like this doctor, go to that one. Don't want to pay this money for all the options on that health care plan? Here is an alternative cheaper one that doesn't cover quite as much.
When you have the government run it you start losing the options. And you don't have the option to picking up your money and taking it elsewhere. Unless you are open to moving overseas.