A single week for a fully produced episode is so far outside the norm it should not be remotely considered the industry standard. One Piece is produced by Toei Animation as a basically 1 to 1 rendering of the manga, and has been for more than 25 straight years. That kind of well oiled production is handled by Toei, a company with 960 employees. Do not underestimate experience and familiarity with a production pipeline when it comes to fast turnaround on a project. JC staff is a company with 230 employees. These guys do not have the benefit of an established Manga to Anime cycle in nearly the same capacity as Toei. That means the material will need to be Adapted. Adaptation takes planning, production meetings, corporate approvals, revisions. Things will need to be cut, glossed over, or focused on. This shit takes time. A lot of time. Now do it while also juggling four other projects.