Yeah, objectively speaking there's quite a lot of shit anime and manga. The things that are good are more or less few and far between, and the things that are bad are the most popular. What I feel really kills a series is the fact that, in their manga serialization, they can be so massively subjected to change. Like, Sakigake!! Otokojuku! is a really classic shonen series from the 80s, one of the better-selling Shonen Jump serializations actually, and even then its story completely fell apart by the end because the author pretty much got axed because of falling popularity. Though, to be fair, he did kill off the same main three of the cast atleast 3 times in the story, only for them to miraculously be okay by the next arc.A lot of anime sucks.
Miyazaki was in the right for retiring from animation. Because the rest of the anime and animation world couldn't compare to his awesomeness. He saw all the crap being made and was like, "Here, let me give you all a handicap."
Dragon Ball GT had a lot of potential to surpass both the original and Z.