This misconception illustrates a lack of knowledge of copyright law, and the reasons why it exists.
The first case I cite is one that shows, beyond a doubt, that you cannot change your copyright license and then expect it to cover things you've already sold and/or granted rights to.
It is against Federal law to change a copyright and attempt to make it retroactive. See below.
Reposted from: http://www.mofo.com/news/updates/files/13228.html
The Second Circuit Court of Appeals ruled last month that all retroactive copyright transfers and licenses are invalid. In Davis v. Blige,—F.3d—, 2007 WL 2893003, 84 U.S.P.Q.2d 1353 (2d Cir. 2007), the court found that “retroactive transfers violate the basic principles of tort and contract law, and undermine the policies embodied by the Copyright Act.” Although the decision appears sound under the facts of the case, its broad conclusions could have far-reaching effects in the world of copyright licensing.
Sharice Davis, a co-owner of two musical composition copyrights at issue, sued Bruce Miller, the alleged transferee of the rights of the other co-owner, Bruce Chambliss. Davis also sued a host of alleged licensees of the disputed compositions who obtained licenses from Miller and others, including recording artist Mary J. Blige. According to the district court’s summary judgment decision, Davis v. Blige, 419 F. Supp. 2d 493 (S.D.N.Y. 2005), Chambliss and Miller documented the transfer of Chambliss’s interest in the disputed compositions after the defendants recorded and distributed the disputed compositions—in fact, the transfer was not reduced to writing until the day before Chambliss’s deposition in the case. Chambliss and Miller claimed that the writing merely ratified an earlier oral agreement that Chambliss would grant Miller certain rights in the compositions, but the district court held that the existence of this alleged oral agreement was a genuinely disputed fact issue. Nevertheless, the district court granted defendants’ summary judgment motion based on its view that the disputed fact issue was immaterial, because, in the district court’s view, past infringement could be cured through the grant of a retroactive assignment of the Chambliss copyright to Miller.
Also see the comments on this article: http://www.techdirt.com/articles/20090408/2314274447.shtml#comments
"Congress wasn't allowed to make the new terms retroactive; it would have been unconstitutional. As mentioned, the "Takings" clause of the Fifth Amendment doesn't allow the government to arbitrarily remove your existing property rights."