Based off some of the other comments, here is the idea I’m picking up on:

If a particular market isn’t that competitive and has oligopolistic aspects, more transparency may increase the “effectiveness” of the oligopoly. Instead of hospitals that were charging more lowering prices to compete, we could see hospitals that were charging less raises prices because they know the competitive pressures are weak and they don’t want to leave money on the table.

Seems plausible to me, depending on how oligopolistic most hospital markets are.