Good post, Svend.
I'm being careful here ... I do not intend to disagree with anything you have written, - I'll just try to bring to attention some of my thoughts here;
"Academics" - Well there are academics and there are Academics ... this is a broad brush, and I don't think it is adequate to define the term for any useful purpose. There are academics that try to nurture a thirst for additonal learning, to "jolt" the students closed area of interest into something wider, to discover their inherent goodness; and there are those whose only mission seems to be the opposite - limiting and decreasing the area to conform to their own closed "world".
Come to think of it ... I think "Critics" fit those molds very well.
Academics of either stripe are as varied as anyone else in the General Public. Certainly they are not infallible, nor are they "gods", nor are they the ONLY discoverers of "Great Art' - left dormant for all those many years. Significant ... yes, arguably ... but not sole.
Another item for comment: "Art must show a mastery of technique (this is NOT meant to argue out you opinion, only to add another one)..." Well, yes ... but the question arises, "WHAT techique is that?" Certainly photograms - as an example - have been produced that are universally considered to be "art" ... even though they were the first, stumbling attempts at the technique. Every significant photographer, and probably this is not limited to photography - has reaped the benefits from departures from "Masterful" technique. In the words of Ansel Adams; "Thirty percent of the world's great photography is the result of fortunate mistakes."
"Great artists have discussed their works ad nauseum". Undeniable - but again, NOT all of them. Some are "VERY* private people, some believe that "If a work HAS to be explained, it is a failure." I would suggest that the variability here is as great (internally, I believe it is still greater) as it is among the general public. I DO have to suggest another possibility: I am convinced that there is another category - those who CANNOT discuss their work because they HONESTLY do not conscioulsy KNOW how to do that ... what "sets their work apart" from anothers.
There is so much more .... I've GOT to get to my darkroom.