This is a valid point.
So how do we compensate creators who are deceased?
Do we let the magic die when the original copies of a book/dvd cease to exist?
Do we compensate a 3rd party who didn't invent the trick?
How about Erdnase? Who should be compensated for Erdnase?
Point one) Thanks to Disney, the copy right will never run out on these books. Meaning the estates of the creators will own the rights to the books and other copyrighted releases. Remember, as of right now you can't copyright the method but you can own the copyright to the printed or video of the effect. I hope Teller wins his lawsuit so magic creators can start to copyright the methods. This is why in the back of the Tom Stone book he went so far as to talk to rights holders for some of the older books.
Point two) Some of these books were put out in small print runs at really high prices to make sure that only those who were working performers or historians would have a copy and to keep them out of the hands of the mildly curious. So no the effects will not die but will be passed down from mentor to student or sold at even higher prices to keep it a exclusive effect.
Honestly, most of my working material is either original from Tarbell or from long out of print books and magazines from the late 1800 to the 1960's I was lucky enough to know a collector who was moving and didn;t want to move his stacks of magazine. I picked eighty years worth of periodicals for about $200.
Point three) Yes if they are the legal copyright holder of the original works.
Point four) If Erdnase gave the publishing rights over to the company who first printed the book then it was their's to do with that they pleased. To sell the rights to whom ever they chose. If the work has fallen into public domain (to be honest i'm not sure if it has or not) then anyone can put their version of the book.
http://fairuse.stanford.edu/overview/public-domain/welcome/
The term “public domain” refers to creative materials that are not protected by intellectual property laws such as copyright, trademark, or patent laws. The public owns these works, not an individual author or artist. Anyone can use a public domain work without obtaining permission, but no one can ever own it. An important wrinkle to understand about public domain material is that, while each work belongs to the public, collections of public domain works may be protected by copyright. If, for example, someone has collected public domain images in a book or on a website, the collection as a whole may be protectible even though individual images are not. You are free to copy and use individual images but copying and distributing the complete collection may infringe what is known as the “collective works” copyright. Collections of public domain material will be protected if the person who created it has used creativity in the choices and organization of the public domain material. This usually involves some unique selection process, for example, a poetry scholar compiling a book
