I've tried to do that for relatively routine care and it's a headache and a half. I spent half a workday (because, of course, I could only do it during business hours--good thing I have a job with a flexible schedule) calling up doctors' offices and waiting while they figured out how much they charged for a new patient appointment. If ZocDoc reliably had that information, it would make shopping around easier (my insurance had a directory but most of the price info was wrong).
In the absence of that, it's just not so easy to shop around for medical care.
In the absence of that, it's just not so easy to shop around for medical care.