The only major fly in the ointment for American copyright holders could be the lack of a similar international standard. The European Union has shown no inclination to go along with the lengthy U.S. copyright extensions and it remains to be seen what, if anything, the E.U. will do if its citizens exploit materials that have passed into the public domain by European standards, but are still protected in the U.S. by virtue of the Bono Copyright Extension.
It is hard to say what effect this sort of elongated copyright protection will have on retailers. While copyright protection is certainly necessary to protect the rights of creators and companies who invest in promoting and nurturing copyrighted properties, the question is how long is 'long enough,' in terms of copyright protection? If all pre-1949 movies were in the public domain, wouldn't we see more of them available on DVD than we do now? In Japan, where amateurs can, because it is a far less litigious society than ours, create and sell works using established copyrighted characters (doujinski manga for example), the practice has certainly not worked against the interests of the major manga publishers, even if the amateur artists depict, as they often do, squeaky clean characters like Sailor Moon in graphic sexual situations.