Who was the most valuable member of the mafia if we go from era to era? Who were the guys that the mafia could not have succeeded financially or politically without? Some would say Lansky or Costello during their time. Gambino is another one, Catena and Franzese were all tremendously wealthy and were some of the most valuable members to the mafia because of their ability to generate so much money and they were able to make important connections in high places.