Earlier quoted context omitted.
That's probably true but a lot of medical cost is scheduled like follow up or specialist visits, surgery and things of the less urgent nature.
How is that solving the car crash situation?
I'm not saying this makes for some total solution - just reacting to rejection of the market dynamic having any worth. It's foolish to cast aside entire paradigms of approaches because they don't fully solve every corner case. (The dual would be to ask how single payer healthcare solves purely elective procedures like cosmetic surgery. It doesn't.)
Obviously any market dynamic for urgent care needs to recognize that no contract has been formed, and so hospitals can't unilaterally set charges under a fallacious idea of contract. For instance when your car gets towed under duress (accident on the highway, expired papers, etc), the state sets the rates they're allowed to charge. They're still inflated, but at least within a factor of 2-3x the usual market.
(FWIW I think single payer is a good pragmatic way forward)