However, if you (or more likely your employer) choose a bad insurance company, it could bankrupt you or cost you your life when they deny your claim for treatment.
With a private insurance company, once you make a costly claim, you are nothing but a potential loss to them that they are desperate to get off the books, so they may deny that claim (with the PRIVATE death panels that already exist). Your only hope is to get media coverage to shame them into changing their mind. The only people who have clout with the company are major shareholders. It's a one dollar one vote system, and when you cost more than you give them, you have no vote.
In a government run system, if you were denied a claim, you would at least have recourse to complain to your elected officials who in turn could pressure bureaucrats. That politician wants the vote of you, your family, and friends.
I like one person one vote more than one dollar one vote.