Wrong again.
Why would you argue this -- I do these tests and manage thyroid patients every day.
Proper thyroid mgt should include free T4, free T3, and TSH. Status of anti-thyroid antibodies also must be known. There is seldom any one test that totally dictates treatment, rather the patien's own symptom-free normal range, historical individual dosing based on absorption variables, and concomitant medications are all necessary considerations.
Essentially every complex product developed has had to be proven before being accepted and routinely used, by several scientists, techs, engineers, etc. We should only be comfortable with a product after such safety and efficacy has been objectively proven, and medicine does an excellent job of that.
An "alternative" doctor is one whose practice does not follow established scientific foundation.
Your example of fibromyalgia is no different than many other medical dilemmas that do not have a definitive cure or palliation. If that frustrates or even angers patients, then they may indeed feel that the system has failed them, and so they seek help elsewhere. In the example above, several categories of medication are capable of improving pain and debility, but they may not be as successful or as well-tolerated as desired.
In FredBeard's case of GBS, his minor early presentation and rapid access to treatment bodes well for a speedy complete recovery.
But there's no guarantee, and that's not what we want to hear. If he has any permanent nerve damage (rare), there will probably be folks who say his care was mismanaged.
Nothing in life is certain.