I think you hit the target when you said you'd go back to the doctor only for something catastrophic. That's what modern medicine seems to have become, merely damage control in catastrophic situations.
The average doctor can save you after a car wreck, or take out your gallbladder when it's beyond recovery, but don't ask them for advice on how to stay healthy in the first place. To think that they let people leave their offices without giving them a word about their plaque-stuffed colons or their stone-choked livers...
Maybe it's just that there's no money in helping people stay healthy, but that's probably getting a little too cynical. It's probably just ignorance brought on by some of civilization's basic assumptions about the superiority of Science and industry over natural living. Our modern food products and modern medicines have the benefit of new technology, so they must be healthier than something archaic.
A fine example of this attitude is that popular annual event, the Race for the Cure (for breast cancer). Why spend your money on some future high-tech cure? Why not Race for the Cause instead?