Interesting read - the comics retail model does seem to be about as conservative as you can get, so while it's not really built for any kind of huge successes (or at least not on any kind of regular basis), the number of huge failures seem pretty minimal too (I think?)
Evan Dorkin talked about this on his blog recently - http://evandorkin.livejournal.com/273883.html
- and I couldn't really think of any series from the big publishers that were big money losers. For smaller publishers, I guess it's much easier for a less succesful book to really hit hard (especially if it uses an expensive propery - Dorkin mentions SLG's reprints of his Bill and Ted comics being a bit of a bust because of this) but as far as the big two go, it seems like while ever their big comics might be torn to shreds critically, you never really hear about them doing terribly financially, or at least not in the same way that you hear about big movies doing awfully. Huge difference in scale, but yeah. It's interesting.
(Also, THE MANHATTAN PROJECTS that gets mentioned in that blog Chris posted is really awesome.)