“The stories told in Japanese manga and anime are incredibly powerful. I often find myself wondering, ‘What is missing in Western comics, and why aren’t they able to achieve the same flavor?’ Also, I think manga has an ‘advantage’ over American comics, which are mostly about superheroes, and that’s where the majority of sales and readers are concentrated.“
Even with one piece, it’s building to something, there will be an end at some point where the story will be wrapped up and there will be no more one piece, it’s not gonna just go on forever (when that ending will be is still debatable but it is allegedly in the final saga now, which could conceivably stretch on for a few more years)