We can't be sure if the "experts" have listened to everything.
For instance, Donald Tovey said of Beethoven's Missa solemnis: "There is no earlier choral writing that comes so near to recovering some of the lost secrets of the style of Palestrina."
But look at "Missa in Dominica Palmarum" (1794) [...]
The earliest generation of "experts" neglected X, then the next generation could also, then the pattern continues, until X falls more and more into obscurity. I'm just saying it's not an impossibility.
What do you mean by "extensive knowledge of music", if a person calls himself an "expert" of C.P.E. Bach keyboard music, for example, but cannot pass tests like [50 Unidentified Excerpts from Carl Philipp Emanuel Bach Keyboard Sonatas
]- would you still consider him an "expert" in matters regarding it? What you're suggesting might be "blind submission to authority."
It doesn't matter how many of these people there are, they still won't know. Isn't this common sense? Y
ou know the Bible even without reading it? A person who has read the Bible 10 times carefully has greater chance of knowing what's inside than a person who only skimmed through it once.