I just realized I haven't tackled the "retail intelligence" aspect of this blog in an awfully long time, so.... There's a few obvious things, like (esp with Humanoids) merely reprinting the same material that a lot of us still had on our shelfs, except the originals were larger and in hardcover, or the real lack of promotion and publicity; and the failure of the line, I suspect, comes from not being able to properly crack the bookstore market (Go use your eyes: the racking of "western" comics material sure seems to have SHRUNK in the last few years in bookstores)
But I can tell you, real easily why these books didn't do as well as they should have: TOO MANY OF THEM in TOO SHORT OF A TIME FRAME.
If I were you, I'd be reading this as the first step in a market correction for perennial items -- there simply isn't the budgets and rack space for the amount of "permanent stock" items the publishers have been trying to plow through the system for the last year or two.
Hm, I guess I just figured out what I'm going to write for Friday's TILTING, so let me drop a few ellipses, and trail off until then....