Difficult to predict, the future is. - Yoda.
Lets look at the recent developments.
- D&D Essentials just came out, to generally positive reviews. Its turn-around time was fairly quick, and it incorporated errata, new ways of doing stuff, and some alternative sub-systems into the 4e game. Its recent push of new material (much of it "evergreen" rule books and starters) leads one to believe that they intended it for more than just one year.
- WotC has just released a new character builder, and has plans for a new monster builder and virtual table top. Software needs long lead-time, much longer than even the game books themselves. By the time they finish debugging the online tools, the new ones would have to be ready for a new edition.
- There were no annual WotC layoffs. This means they are at or below acceptable team-levels OR they are bulking up for new development.
- Several early-released books disappeared off the radar. This included updates to the PHB (Heroes of Swd & Spl) and the Nentir Vale gaz. This can mean a lot of things: the material isn't ready (due to lack of development time), its being held to puff-out the latter half of 2011 (possibly due to other cancellations), or they are killing the products to prep a new edition (2000/2008 all over again). The last possibility is that they are winding down D&D products altogether due to lack of energetic sales. (Aka the Doomsday scenario).
- D&DMinis and Heroescape have both wound down to next to nothing. This bodes poorly to the mini-heavy 4e, and pogs/tokens have taken they're place as a cheap alternative.
- Pre-Essential material (such as PHB3 and MM3) didn't sell as well as Core 1 and Core 2 releases. This is the reason for a lack of DMG3, the ending of the PHB/DMG/MM a year schedule, and perhaps even "classic" itself. Only Dark Sun bucked the trend.
- D&D Neverwinter is still in development and supposed to utilize the D&D 4e rules. Its unclear if they are the Classic or Essential version of the rules. In theory, it could be changed to a mythical 5e.
- Dragon/Dungeon Content is thin. This bodes poorly because it means they aren't getting enough submissions, or they are withholding material (see books, above).
- Thanks to the thinning content, the char-builder debacle, and problems with monster-builder and the compendium updates, there seems to be a rash of DDi account cancellations (anecdotal, at least). That could mean a cash-flow loss.
- 4e, despite inter-compatibility, is now two "branches", Classic and Essential. WotC appears unable or unwilling to support both except through token measures (sparse Dragon material). The material canceled seems to be generally classic-era material. Perhaps this is to make room for more Essential-era material?
What does all this mean? Either...
a.) Essentials did better than anyone at WotC hoped, and they are quickly recalculating their product lineup to take into account their "new" D&Ds success, phasing out "classic" support altogether.
b.) Essentials did well, but not well enough and they are gearing up for a major new revision/edition/marketing blitz to try to win back the numerous fans they lost in various 4e-era debacles (the roll-out, DDi, PDFs, etc).
c.) Essentials did well, but not enough to keep D&D as a primary WotC cash-cow. Material will be thin from here-on-out, leading to an eventual shelving in 2012/13.
d.) The Unquiet ghosts of Gygax and Arneson have wrecked havoc on WotC.
A is optimism. B. is desperation, C. is Despair, and D is probably true.