I read this book this past summer just before starting med school. I think it's a great book and it would be great if all patients and their doctors could read it.
If you read the whole book, Dr. Groopman does, at least partly, go into WHY many physicians don't think more "outside-the-box." There are several reasons, but one of them is that docs are pressured to see more and more patients (partly because they have to pay higher malpractice insurance premiums, which is partly because more patients are bringing up frivolous lawsuits against them).
Another one is that with the explosive advancement of science and medicine, we are expected to keep up with gazillions of new pieces of information and research every single day, but medical training itself takes essentially the same amount of time it did 50 years ago. I think people tend to ignore this extremely obvious fact. Though I would hesitate to voluntary put myself in the position of a med student for even longer than four years, it probably wouldn't be the worst idea in the world.
I could go on and on, but my theories about the theories of medicine are probably pretty boring...although I feel pretty lucky to be able to come at this issue from both points of view!