This.
One Piece is also way more popular than either Bleach or Naruto in Japan. I have no idea why it hasn’t caught on big time in the states.
It wasn’t released very well. It was erratically put out, poorly marketed, and the show really does drag: you could cut each episode’s time in half and leave nothing interesting or vital out. I like One Piece, but like the original DBZ featured episodes could be cut down without losing much.
I think it’s because the storyline of One Piece is more complicated than either Naruto or Bleach. The two latter are relatively easy to pick up halfway and read the previous manga (or watch older episodes), whereas you have to have at least some context to enjoy One Piece. I tried to watch it from the beginning, but couldn’t get past the second season because I just didn’t have the time to sit around watching episode after episode. It’s a shame, too - I really would like to watch the Alabasta and Ennies Lobby arcs, but I’m not sure how much more I need to watch in order to understand what I’m watching.