I think that what you describe (at least in the first half) is largely a matter of rights ownership. If an artist signs away the rights to an album or a book or a movie, then the owner (usually a big corporation) is unfortunately within their rights to bury it so that it never sees the light of day. They are free to distribute it or not distribute it, and often the artist is often left with little recourse if they decide not to distribute it or (god forbid) distribute it in a watered down form that is not at all what the artist envisioned.
I think that this could be addressed with changes to contract law that would give artists recourse (specifically: the right to shop the work around) when the rightsholder attempts to bury a work that an artist sold the rights to with the assumption that it would be distributed. The big companies have all the power in these situations, so clauses to that effect are rarely baked into the contracts that the artists sign.
