User blog comment:The Koromo/Things You Love in One Piece (That Everyone Else Hates)/@comment-5640399-20130823014342/@comment-6920514-20130823042653

Regarding the question about the old members of DD's crew/family I believe is because they were already in place from the previous leader of the family. Kinda like Al Pacino taking over for Marlon Brando in the Godfather except this mafia family is either royalty or some deep-rooted royal connections. The dwarves did say that their feud with the Donquixote family dated back a thousand years and there's been heavy hints about the World Nobles so probably they are the remnants of the previous group