manga, like I do and I'm assuming a number of others here, you aren't necessarily watching to see the outcome (since you already know what's gonna happen). It's just a matter (for me anyways) of seeing the fights come to life.
Even though I'm not a fan of the effort (or lack there of) that the animators put into Bleach, I think they're budgeting they're money. You can only produce top quality episodes for so long, before funds become an issue. I think they're just keeping it low quality for the regular episodes of plot development, smaller fights and such...and then when they reach a major fight, they put some more money in, and up the quality. The only good thing I can really pull out of it is that we appreciate the high quality episodes we get that much more when we get them, since they're so few and far between.