Yep, fully agree. "researched, documented, and analyzed properly" is a very particular method of doing things, and much of the music pedagogy is pretty much "it worked for me and I'm good (or it worked for them and they're good), so it will work for you too". Which is true sometimes and very much not true other times. It's often a very conservative field (not in the political way, but in the sense of resisting change/doing it the traditional way), so if someone comes in and actually studies things with a more scientific sort of approach, there's no guarantee it will be accepted or catch on.

At least in the family of brass instruments, I am fairly confident that they're largely still living in the dark ages and often don't understand fundamentally how the instrument is even played, at least from a scientific/physical perspective, so good luck if you end up with a teacher/professor who expects you to play one way when in reality you'd probably be much better off playing another way. This happened to me early on and I eventually learned that there has in fact been some pretty good research and documentation into brass technique but it's pretty niche and lots of music professors pretty much entirely disregard it because of the above point about it being a very conservative field. Donald Reinhardt is kind of the one who kicked off a lot of that movement but there's a number of people who have been carrying on that work.

If a similar thing has been happening in the piano field I wouldn't be at all surprised (although I do think that the brass field is particularly ripe for things to go rotten in this way just because the brass embouchure is particularly complicated and also hard to observe).