DTB/DTW status changes on a regular basis as people put up results with decks and some decks move up and others down. It's purely result based with quantity of top 8's being a key factor.

There are a number of very good decks that would place well in more tourneys if they were played more often and would move up to the DTB forum as a result. They don't get played that often for whatever reason and thus they do not wind up in the DTB section.