The thing about Bleach is that there is a lot to be said about a series that everyone reads, but is no one's favorite.
Right, I mean, it was huge back in the day so many people ended up reading it, I mean most of JUMP's readership, and most of those people who buy the magazine probably end up reading Bleach, just to see it through to its end.
People who bought the volumes for collection value will keep buying them, so they can finish the set.
Basically, for the most part I think a large percent of JUMP's readership keeps up with Bleach at least begrudgingly if not enthusiastically. The problem is that it's no one's favorite, and so no one is voting for it.
But JUMP doesn't care if a series is your favorite: it just wants sales. If BLEACH is read, and BLEACH merchandise sells, it's a success. Even if all the millions of readers will continue to say, "yeah it's my least favorite series but I'm too invested at this point, so I just buy the volumes to complete my collection" that's a success.
So BLEACH, so long as it sells and its merchandise sells, is far more successful than almost all the series that consistently rank above it.