On the other hand, there really are things the lay person can learn and understand well, even in the complex human body.
I have an unusual, if not rare, condition (Crohn's Disease, which GPs now usually seem to have a decent handle on, but that wasn't the case 20-30 years ago). I've had the condition for over 30 years. Barring advancements in science (which I follow anyway) and other possible complications (which I would be discussing with my GP and GI docs anyway, much of what the system forces me to use them for is not only a waste of their time, but problematic for the patients like me because it forces me to wait for an appointment to get the necessary care.
When I have a flare-up, I know exactly what needs to be done. If I walk into a GP's office, or even a GI doc, all they're going to do is rubber-stamp the prescription I know I need, and ask me to come back later to follow up. I already know what I need, the system is just wasting everyone's time, and withholding necessary care.
The thing is that the human body doesn't really follow a strict blueprint: my own deviation from the norm is the reason I'm there in the first place! So by definition, the doctor can't just give me a textbook answer. It all depends on the way the disease affects me personally.
Now, it's true that I may not have sufficiently broad understanding to see when a complication is arising, to handle it specially. But that's no reason to forestall proper care. I'm perfectly capable of starting the treatment on my own, and visiting for further consultation in the timeframe that first available appointment allows. (If such a consultation is so critical, surely getting the treatment rolling is just as much).
But the way care is delivered now, the doctors comprise a priesthood to which we must show obeisance. In my experience, the system could work both more efficiently as well as more effectively if treatment were more of a partnership, with the doctor contributing the deep understanding that he's worked hard for, but a patient also contributing based on the very focused opportunity to learn about his own condition, especially given the unique and personal ways that illness can affect each of us.