Well, I think it would have to start somewhere. I'd be happy to be able to comparison shop for routine, non-emergency stuff...let's say dentists to start off with. I have a feeling that once you start chipping away at it, the outlying examples would get taken care of as well.
There was a similar thread a few weeks back:
https://news.ycombinator.com/item?id=6258597
It'd be great if the HN community started throwing out some ideas for disrupting this behemoth.