I think there is a vast pool of recordings out there that your
discussion excludes that are equally or more in need of preservation
as they are unique. These generally fall outside of the copyright
discussions we have been having, although it may not be 100% clear as
to who owns the copyrights and whether they are even copyrighted. I
am speaking of tapes like your piano student's and the vast archive
or oral histories that have been made in many areas.
Yes, I have left them out as my vision is too often myopic...limited to my
own interests.