With DVD-+RW prices falling I can see a point at which manufacturing CD-R/+RW will become unviable. The costs will mean that it is more economic to just go with DVD-+RW drives.
The same may or may not go for CD-R/+RW media. Although the cost of DVD-+RW media is still overpriced IMO (Even if relative to CD recordable media it is actually better value if you only buy the cost effective brands and not the brand name stuff complete with their packaging).
I’m holding off upgrading to a DVD rewriter as I am waiting for a point whereby CD rewriters are going the way of the dodo and DVD rewriters are not just very affordable but whereby the media is closer to current CD-R media. Of course I don’t expect DVD media to drop to the price of CD media for a long time (If at all) but if it was half the price it is now then I could see it being very much worthwhile.
Also what with dual layered recorders and media nd 16x recording around the corner I can see that being the point (Along with cost of) at which it will be explosive in a sales perspective.
Then we can move on to other storage forms such as Blu-Ray with 4 layered discs holding 100GB on the horizon