Healthcare can never, never be affordable unless there is some spending cap or limit on how much medical treatment a person can get. There will always be some new experimental procedure or drug that costs hundreds of thousands of dollars and has a low rate of success that will drain any insurance pool.
How much money do you put into a car before you decide to junk it? At some point it makes financial sense to stop fixing a car. Problem is that you can not easily make that logical decision about people. So at what point do you stop treating someone who will die any way? Who wants to make that decision???