That's what insurance does.

Some events are extremely rare and extremely expensive. We shouldn't expect every individual to have enough savings to pay for every eventuality.

Sharing that risk allows nearly everyone to live better.

The question here is whether that insurance should be provided by a profit-making corporation or a government agency.

Though the US system of private insurance is badly broken, evidence from other countries shows that both approaches can work.

Yeah, interesting question. But in the US, the problem right now is 26-year-old diabetics kicked off ACA plans who have to ration insulin (a drug invented a century ago, given royalty-free to the world by the inventors). Sometimes the rationing fails and they die.

So the question should be - can we as a society afford decent late 20th-Century-standard care to every person? The answer is yes, we can, but we don't.