true; there is no reason to disclose special secrets except for pecuniary value; philanthropic offerings of music tips will only be given to an extent, as anything more than that would give free reign to their secrets as the above post stated
Well, that's a bit more an acid tone than I would have used, but this is an excellent chance to say what I believe to be generally the case: there's a value in research, done typically by universities and places like the US Department of Defense. Yeah, I'm being a bit sarcastic, but I'm also right, even if we don't live in a perfect world.
Not perfect, obviously, but in music and in life, cui bono is not a bad question to ask.
And, just from experience as a 40-year-old musician, I don't think anyone can possibly argue that musicians are, generally, a pretty cagey bunch.
It's not my intention to suggest one be paranoid about every bit of advice given -- just that, in my experience, it's better to look at what people actually do, rather than what they say.
So, generally, that's why the recordings are the real source for jazz -- there's just too much bloviating among "jazz theorists" to take it seriously. It's pretty simple, since there are only so many records of jazz -- just transcribe it and pauca intelligenti, remember that the people who propose some systems, are not any more likely to be correct than anyone else.
That's how you get aberrations like melodic-minor mode "theory" or John Mehegan's "rootless voicing" theory. They're fine and useful up to a point, but they're not rooted in theory. Good reading, but not important examples.