Many of the current releases are chock full of recycled art. Grand History of the Realms being an excellent example. And before you start saying that it would make sense that a giant timeline would feature the art reflected from the history of 3.0/3.5e Forgotten Realms releases, I would add that some of the art has absolutely nothing to do with Forgotten Realms.
One example is a piece of art I immediately recognized from Oriental Adventures (2001) of the Void Disciple PrC (OA, p. 52), a concept originally adapted from AEG's Legend of the Five Rings. Not that this sort of thing bothers me personally, but there's really only one reason for it: The majority of the new art (and the money set aside for new art) is budgeted for 4e.
EDIT: I should really have taken a look at the Rules Compendium art gallery before writing this post. Apparently that same piece of art (by Matt Cavotta) from Oriental Adventures that made its way into Grand History of the Realms also appears in the Rules Compendium!