"One Piece" anime and other series like manga and video games have continuously held the interest of its fans. There are 3 things that set this anime apart from the rest.
In Anime series and Manga series, the 3 contenders that fight for the number 1 spot are One Piece, Naruto, and Bleach. However, among these 3, One- Piece has not lost its momentum and has pique the curiosity of its fans one episode or chapter after another.
Design N Trend says Naruto may have the greatest runs against other anime series, however it fails to end well. Naruto appears like it rushes its way to the finishing line, although there's so much potential in the material as far as character development is concerned. The same goes for "Bleach," which had a good start but then in the end it was canceled prematurely.
What could have gone wrong with those two great anime series? Or what is in "One Piece" that is not present in "Naruto" or "Bleach" or any other anime series?
One obvious factor is the devotion of the creator towards his craft. Eiichiro Oda is commended for his devotion towards making this series. This is not to discredit Kishimoto and Kubo, and it doesn't mean that they are not devoted. But Oda is simply being praised for his devotion to his comics as it is unwaveringly translated in his works. Viewers can see how he devout himself in developing not just the main character but almost all the characters in the pirate anime. The characters are part of the progression of the story.
Because of the Oda's effort in writing great character development, fans feel that they are a part of the story. This is the second factor that sets this show apart from the others. It says that "the story's length and balance, it also feels as if you have been alongside the Strawhats in their quest for One Piece."
Third reason that makes this anime a standout is that Eiichiro Oda has already envisioned how "One Piece" would end. Other writers like Tite Kubo and Masashi Kishimoto have given up in their creation, telling their avid readers and viewers that they are no longer interested in writing their recent creation. Once the writer contemplates of writing another anime or manga, this will affect the current comics (printed or animated) and the story will somehow no longer make sense, which eventually put the show to its untimely death. Since the author has his vision of the final outcome, it will maintain its momentum until the end.
Now speaking of final ending, Youth Health Mag says that "One Piece" may reach its final adventure in 2020, as revealed by Oda. He said that the final chapter would be amazing. He also mentioned that the "Greatest War" would be far "greater than the Marineford Arc." Suguru Sugita, who works with Oda as Manga editor, admits that they're already 70% done with the work considering they have produced 60 volumes already since 1997.
Granting that the anime has finished 70% of its work, which took the creators 18 years, "the remaining 30% would only take about five to eight years more." So roughly, the anime would end sometime in 2020 or even 2023. This means fans could still have a lot of time to enjoy the anime series.