MaelStorm said:
The argument of trying not to force too many book on their consumers. Have you seen the WotC lineup to 2009 at DDXP? Draconomicon I is more important than bards and druids!
EDIT: What I get from WotC is that more profit is important, than release a complete product so they can sell it later on.
In some ways it is. People like dragons, they get a lot of request for dragon material and everything they've put the word dragon on sells better than other books.
However, I can also see that the books aren't directly competing against each other.
It seems WOTC started making about 15 different classes for 4th Ed at the same time. When they realized the page count that each class required due to having their own LONG list of powers, they realized they couldn't put more than 8 classes in the PHB.
This meant that some of the ones they'd been working on would have to be delayed until a different book. Made sense for new classes to be in the PHB II or PHB III. However, you don't want to release a whole bunch of books that people will want all at the same time. You want to space them far enough apart that people will be able to afford all of them. Plus, you want the game to keep going for a number of years to come. If you release 25 classes right now, a book of 1000 magic items, a book of 1000 feats and a book of 1000 powers, then you pretty much have published everything anyone will need for the next 10 years of gaming. Not only that, but the amount of work required to complete that is more than can be completed in the next couple of month.
So, for the health of the game, you need to split all of those options up over a number of books that come out slowly.