Your comment seems to suggest that healthcare is an infinite resource. It isn't. There are a finite number of brilliant surgeons, a finite number of expensive MRI machines, a finite number of hospital beds, etc.

A market is just a means of determining distribution of a rivalrous resource. If it wasn't money, it would be something else (influence, political power, etc).

Having money, in general, is a proxy for the ability to create wealth. Thus, if you can't save everyone, and you have to use some mechanism for choosing who to save, then choosing to save the rich is a decent proxy for saving the people who create wealth. I happen to think that's a better system than some of the others ('who you know', 'how "good" your politics are')