> The problem is that it's an inelastic market. So sellers can basically charge WHATEVER they want, constrained only to the line where people will revolt.

What keeps me from bringing my business too the competition like I do in every other market? The main constraint I see right now is that there are very few, but large hospitals and my insurance only pays for me to go to even fewer of those. However, competition already works (if the patient makes an effort) for some planned procedures like CT scans where you can safe up to 80% in my own experience.