Why aren't there more characters who uses Rokushiki? Like if you

Rokushiki, All Worlds Alliance Wiki

One Piece: 8 Characters You Didn't Know Could Use Rokushiki

One Piece 1068 brings back Lucci's Rokuogan

How good is Luffy (One Piece) in hand-to-hand combat, for example, Taijutsu? - Quora

In Another World, One Piece Role-Play Wiki

In One Piece, why do the members of CP9 learn to use the “six powers”, but not haki? - Quora

Why aren't there more characters who uses Rokushiki? Like if you spend your whole life being a swimming champion only to have to eat a Devil Fruit that throws away those years

Is Rokuogan and Ryou, both same or different skills? I have always wondered if Rokuogan and Ryou are the same the abilities. Both skills are VERY similar! : r/OnePiece

Is Rokushiki a fighting style? If it is, does Luffy use it? - Quora

How strong would Robin be if she had CoA and CoO plus knew all 7 styles of Rokushiki? : r/MemePiece

Which do you prefer in One Piece, Devil Fruit, Haki or Rokushiki? - Quora

Rokushiki is based on physical strength is actually based on a mistranslation in earlier One Piece volumes : r/OnePiece