Quora Question: Why do doctors blame everything on one diagnosis instead of investigating further?
My Answer: We're trained according to Occam's Razor: if one interpretation explains many findings, it is the best explanation. It is a very solid, very workable approach to not only medicine, but also to life in general.
But in terms of your implication that it precludes further investigation, that is a fault of your particular physician, not the philosophy. I personally have been a victim of that. As a patient, not a doc.