It's insurance. Just like car insurance, home insurance, travel insurance, etc. It's not supposed to pay for everything for everyone at all times. It's supposed to pay for the outlier events, the super events where an accident occurs or a tragic health diagnosis.

Health insurance is not health care.

That being said, I'm not arguing whether everyone should be entitled to free/reduced health care - but I am making the point that insurance is just insurance; it's a hedge against an unlikely but costly event.