Not necessarily when the choices are constrained by the health insurer. We (a big VC funded primary care provider) experimented with full transparency pricing. Never moved the needle. But that was 10 years ago so maybe things are different now.
Agreed, insurance companies are typically a big cog in the wheel. We're starting to see things change as high deductible health plans have grown so rapidly. The consumerism of healthcare is starting to create change (i.e. price transparency executive order signed in June).