In many cases it is because the patient doesn't stay up to date on studies, or has such a limited understanding of medicine, that a discussion of such studies doesn't work well - and the docs have a schedule.

The medical profession, more so than almost all other professions stays up to date on studies, developments, etc. Doctors, as I am sure you are aware, are not "average" folks - they have always been brighter and better learners than their peers in elementary, high school, college, etc - and they are morally dedicated to their patients. This is why we trust them to make the best decisions for us. Do they make mistakes, sure ... is this because they aren't keeping up with studies and technology? No as likely.

My sense is that many who post and complain about their doctors, are not competent to do so - they are simply expressing an opinion. Sometimes patients may know something newer, but not normally.