Why is modern medicine so bad at holistic diagnosis?

I’ve been having some health issues for which I’ve had quite a few diagnostic tests over the past month. Since the concerns are in different parts of the body, each test addresses a particular region/organ and that makes sense to me. The good news is nothing’s been found so far. The bad news is nothing’s been found so far.

Out of desperation, I went to an acupuncture specialist and his diagnosis is that it is probably a nervous disorder which regulates multiple functions of the body. Suddenly, it kinda made sense to me. I’ve been dealing with severe nervousness and anxiety for a few years now and have detailed this to multiple doctors. However, no one has made the connection so far. Now I’m not going to stop regular GP visits or medicines, but I’m quite surprised that not one doctor or specialist had thought about the holistic aspect of my health. It’s always localised and when they can’t find anything, they just call it anxiety.

Why, inspite of so many medical advances, are we not able to see the bigger picture in a lot of cases?!