I have a few observations to make on issues raised by various posters to this thread:
(1) It costs nothing to claim/obtain a copyright. An artist’s work is considered copyrighted, and protected by such law, from the moment of its creation. Thus even unpublished works are considered copyrighted. It is possible to register and submit original works to the Library of Congress for a nominal fee; this probably provides additional safeguards to the existing copyright, but it is optional. (Little Nemo: AFAIK, this is as close as we get to having a central repository of copyrighted works.)
(2) Copyright law is not intended to give artists a financial incentive to produce artistic works. If that were the case, I should be rich by now! It is intended to protect the original artistic works – the “intellectual property” of the author – from misappropriation by other people, in the same way the things in your house are protected from theft by criminal law.
(3) The creation of an artistic work is a separate process from the promotion of that work in the public arena. I don’t write novels because they will be published and I will reap the financial rewards. I have no assurance that either of those things will happen; I write just because I like to write. If I can’t find a suitable publisher, or choose not to seek one out, or my publisher says, “We did a limited run but it didn’t sell too well; we’re not going to print any more copies”, I don’t think that constitutes “hoarding” of my artistic ideas, nor I don’t think I should somehow be compelled to surrender my copyright as a result.
(4) It is understandable that a person might like to have a copy of a work which is out-of-print. But wanting a work is not the same as having a right to obtain it by any possible means. If it’s not in print any longer, and you can’t find an existing copy, then you’re just SOL – or you do something unethical to get a copy. Believe me, I know how that feels, but there it is.
This topic came up in another discussion group several years ago, but regarding something in the music industry. The Swedish pop act, Roxette (stop snickering!), put out their first album, Pearls of Passion, on vinyl (not CD) in 1986. IIRC, this LP was released only in Sweden and Canada; or maybe the singles were released in both places, and the LP just in Sweden. No matter. It did well enough for Roxette to continue, put out Look Sharp! in 1988, and become an international success. As a result, the first LP became a hot item and it was/is virtually impossible to find a copy by any legal venue. Someone like myself, who did not know about the first album until much later but wanted to find it, was out of luck.
Then in the mid-90s, Roxette was considering re-releasing POP on CD. At one point Per Gessle, the male half of Roxette who plays guitar and holds the copyright on 99% of their songs, decided that he was not going to give his permission for the CD release to the record compan. He felt that the material on POP was under-par, relative to the music which came after, and did not wish to re-introduce it into widespread circulation. He certainly didn’t need any more money; he’s the richest man in Sweden after the king, or maybe in spite of the king. Anyway, many POP-deprived Roxette fans were upset by this because they felt they were owed, or deserved to have, this work made available to them, but copyright laws have nothing to do with what fans/consumers want. They allow the artist to exert control over his work at any time while the copyright is in effect. Per was the controlling artist, and so the decision was his, and his alone, to make. Copyrights should not be used to compel artists to do anything with their works.
(Postscript: in 1997 Per relented and EMI released the album on CD.)