Try getting medical care for someone allergic to pred and watch how confounded the doctors are how to proceed.
Medical history is replete with drugs and treatments that every doctor prescribed all day every day, until they didn't. If you had a stomach ulcer in 1990, the approved "treatment" certainly would have included a bland diet. Now they know it's caused by a bacteria.
Sinus rinsing is something else that's been covered here. It is NOT disapproved by doctors, at least, but I don't think it would be the first recommendation most of them would give you.
(We might blame that one on patients who want a drug for everything, or else they're not getting their money's worth.)
The sad truth is that you always have to look out for yourself. You need to take care to read up on your conditions and your prescribed treatments, but don't let that fool you into thinking you've got a medical degree or that doctors are out to get you, or that science isn't trustworthy. Most doctors are doing the best they can to make you feel better using the best understanding of medicine and biology we currently have. You may look at medical history as a series of errors and mistakes, but it really just shows the progress of our understanding.
Things like sinus rinsing have their uses. It may not be the first thing doctors recommend to people, but there are likely several reasons for that beyond people demanding pills. The main reason being a lack of strong evidence that supports it being more effective than current recommendations which may be easier for people to do and/or carry fewer risks. As soon as the data overwhelmingly supports recommending sinus rinsing over current treatments, doctor's recommendations will start to slowly change.
My point is, watch our for yourself and be careful, but don't let bad experiences or bad actors cause you to lose faith in the process itself.
Doctors are not out to get you, but they aren't perfect either.