But finding the right treatment for a patient is almost a random process of going through the dozens of established treatment options available (as well as any of your own devising). You have to keep going, until you find the treatments that work for you.
In a sense doctors do this all the time. Most treatments are not guaranteed in medicine. Doctors have to make a best choice from a limited range of options. This typically involves experimenting on the patient. If the patient does not respond as expected then they may choose another option, and so on down their list. They are trained to do this, though the methods used vary hugely doctor by doctor.
Most of us do not have very experienced ME doctors. Our doctors have very limited knowledge on ME. So its completely understandable that we have to make choices ourselves, though it would probably be better in most cases if patients and doctors could collaborate. However many doctors use an authoritative model, so its difficult for patients to be really engaged in decision making.
I have a new GP. She has already made one bad bungle in decision making, on our first appointment, but don't ask me for names. I am not interested in blaming doctors, but in finding out ways to improve decision making. I will take this particular issue up with her again after I have done a little research.
Doctors have to make decisions on limited and often fallible information. That is the game. Its good to make these whenever possible on sound research and reasoning, but in practice this is problematic. I am finding that even EBM "evidence" based claims are often flawed.
Medicine will advance by sound science, but this takes time, effort, support and funding. It does not just magically happen. In the meantime we, as patients, still have to deal with issues on a day to day basis, whether there is sound science available to help us or not.