While there is merit in that approach, Medicine has tended to neglect the importance of strengthening the immune system, rather than only trying to kill a bug. After fifty years of antibiotic use, we are now one antibiotic away from the evolution of bacteria that can't be killed. Our magic bullets are failing. The initials make it sound safer, but it stands for Multiple Resistant Staff Aureus. In lay terms, it is a staph infection that is almost impossible to kill.
Illness is often infinitely complex.
It's not as simple as identifying streptococcus as the cause of a sore throat. Cause and effect become difficult to sort out when dealing with chronic illness. When you've broken a bone, the cause is evident and the treatment may be in an emergency room where a cast is put on. Surgery is a kind of magic bullet. When treating chronic illness, I often find it difficult to find a starting point that was and is the cause of the illness.