Relatively good compared to what?
And taking what into account?
And to achieve what goals?
My most comprehensive view is that it's not as easy as "selling well" or "not selling well." You have a global economic stinkyhole, a publishing industry grappling with new technology, Amazon, whatnot...but you also have the DDI, the bestseller lists, blah blah blah blah. And even if it's selling fine, it might not be selling up to the level the bean-counters assumed. And even if it's selling horribly on individual books, it might be meeting expectations or exceeding them in other areas. Maybe they had some
redonkulous expectations to begin with. Maybe Mearls's contract demanded a new Ferrari every month filled with fresh caviar, and WotC is feelin' the hurt.
Dudes, we just don't know.
Probably, Wizards is feeling the crunch, economically. I only say that because there's probably a 90% chance that ANYONE in the world is feeling the crunch. Retail sales drop. Less people pop into Borders. Less people happen to pick up 4e while they're lookin' for their pokemans comics.
WotC is probably not dumb enough to go TSR on everything, however desperately some people want to imply that.
4e is probably the most successful PnP RPG out there right now. That might not be saying much, since we're niche city at the best of times, but if they're doing bad, it's not because someone is BEATING them. It's probably also not because people are torqued off about 4e. None of us has ever seen a game printed on a book that is perfect from the outset, so quality ain't what sells a game system (even if you think 4e sucks, that doesn't mean it can't buy and sell your butts).
I believe I've said before that if 4e were FATAL slapped with the D&D logo, it would sell like gangbusters, and while that's hyperbole, we all know that cruddy games still sell in high numbers.
D&D isn't dying or anything. They might be re-assessing some of their riskier moves in light of going friggin' broke, and this might mean more "pandering to the base" by teasing out features of earlier editions that make people pumped up, in hopes of winning a few edge-lurking converts, but they're sticking with 4e 'till at least 2014 (at least, based on the bets I've placed.

), and to try and do otherwise would probably bone them even worse than staying the course and making the best of a bad situation -- which might not even be bad because people don't like 4e. It might just be bad because, I dunno, no one is driving to the mall and browsing at Borders anymore, since we're all broke-smack chumps.
Sorry about the long post, but this subject generally irks me because it's about edition wars axe-grinding on both sides (4e ROCKS SALES, EVERYONE LOVES IT LIKE I DO!/4e SUCKS SALES, EVERYONE HATES IT LIKE I DO), and people loose sight of the big picture because they're too busy wailing on each other for not liking someone else's particular way of dressing up like an Elf on Saturday afternoons.
We're all broke-smack chumps. WotC probably included.
This has little to do with whether or not gnomes were in the PHI. A'ite?