I didn't know about the cancellation of Bleach until early today. To be honest, its not at all surprising to me. I stopped watching the anime the instant Aizen was defeated, and I assume a massive amount of the bleach community did as well. The bottom line is that Bleach has always been third to Naruto and OP, and on top of that, the anime started getting way to close to the manga to be logical anymore.
The only explanation that I came up with was that the animators were under the impression that the manga was ending after Aizen's defeat, and they simply did not plan to implement anymore fillers for that very reason. I mean Aizen was defeated in the anime about 5 weeks after the manga, which is simply ridiculous. For the anime to stay behind the manga after that, there would have to have been about 2 filler episodes for every manga episode... basically a perfect storm for loosing viewers and getting cancelled.
I knew that fillers were eminent after Aizen's defeat so I just concentrated on the manga and ignored my previous liking of Tuesdays (lol). But the bottom line was that the animators completely screwed themselves over, but it was not like bleach was a great manga for anime anyway. I mean Kubo's war arc was so unbelievably long that they literally had to pause the action and take up a new, alternate reality, storyline every so often just to stay behind the manga, it was just bad for anime. Anywayyyyy.... I just think the animators were absolutely slack jawed fools when it came to adding fillers near the end of the arrancar act, essentially spelling their own demise as soon as Aizen was defeated.