I was with you up until this point. Part of the problem is that this cannot be true in all cases, unless either (a) your condition is commonplace (b) the doctor specializes in your condition.

Yes, doctors know more than you in almost every way about bodies about medicine, about drugs. However, people with relatively uncommon conditions have been enabled (largely by the internet) to create communities of fellow condition-sufferers, and the collections of anecdata that result represent a resource that generalist doctors do not have access to. The good specialists, in some cases, will take occasional dips in to augment their own knowledge and expertise.

Case in point: my daughter has had two major hip surgeries. While there is no way anyone in their right minds would have chosen someone who had not performed these surgeries previously (preferably, many times), and while it was completely clear that the surgeons really really really knew what they were doing, it was also the case that various online communities made up of people who have been through this procedure were able to provide lots of information that the surgeons could/would not. This was particularly true of the recovery process, where there were a number of common oddities that most people who have the procedure experience, and they're really not a problem. They are scary however, and the actual medical professionals really had nothing useful to say about them.

There's another issue with the blanket "doc knows best" rule. If you've had a GP for many years, or a specialist helping you with a condition for many years, then it's probably a great rule of thumb. On the other hand, if you've moved, or for any other reason switched doctors, and you're the kind of person who does pay attention to their body, there's a reasonable chance that you're going to know things about yourself/your body that the new doc(s) will likely not be aware of. They can (and will) learn, of course, and there's no reason to be aggressive or patronizing about it. But for example, you may understand the way you typically recover from antibiotic treatments, or the consequences of lack of sleep, or your tendency to always pull a lower back muscle given certain movements, etc. etc. in ways that your (newish) doctor may not yet be wise to.

Objectively, the patient is the only one who has 500,000 hours of experience with the unique and very complicated system we call a body, and is objectively the only one who comprehends what they're feeling. They're also the one who experiences the consequences, they're the only ones with literal skin in the game. How much is all of this worth?

It's a difficult thing. The answer is some mix of giving the doctor and patient power.

I don't think that's necessarily incongruent with the OPs point. If the metrics are being gamed or the metrics are being used to inaccurately gauge provider care, those are systemic issues. Or it could be the case of well-intentioned, but poorly chosen metrics.