I'm not completely sure that the vast majority of the guys in the Five Families at the time of Castellamarese were probably not "made" in the traditional sense.
Luciano, Costello, Adonis, Capone... These were just guys who happened to be of Italian/Sicilian stock who rose to the top of the underworld pile. I think that the tradition of "making" only gained prominence once the family lines had been firmly drawn and they had become the national Cosa Nostra.
^This. Before 1931 some followed the tradition from Sicily and some didn't. It wasn't until Marazano won the war that there were formal rule that you had to be made to be part of a family. Obviously that meant none or few Chicago Outfit guys including Capone were formally made. Like someone said, the Outfit was accepted as a Mafia family by Maranzano.
