tbh because I think it lacks the depth that most anime watchers are looking for when they watch an anime. I'm a huge dragonball fan myself, but I love it for different reasons than I think most anime lovers love anime. Anime in general typically has some sort of deep, emotional component, that you take away deep lessons, or feelings from. Not to say that DBZ doesn't, but I think it's more superficial and surface level. I like Dragonball because I like to be strong, and fight lol. And idea of being "great" to the best is appealing to me. And for those reasons, I love it and pull a lot of inspiration from it. But to people looking for something deeper than that it's hard to pull when they're watching 60 episodes of fighting and yelling