Chicago wasnt really a "family" in its early days, there was an established "family" already in Chicago prior to Capone and his "getting made" by Masseria during rhe Castellamarese War. Regardless , The Outfit was a powerful group, partly because of its willingness to include many different ethnicities, and allow some of those non-Italians, non-made guys to rise up in the organization. Personally I think they may had already surpassed the established Chicago family in strength prior to Masseria coming along, and like I said before there are still Italians and always was, who were in the group and never "made" or participated in induction ceremonies. The fact that they didnt really seem to be barred from anything and didnt follow the typical Cosa Nostra stigmas and rules, I think its aided them now, and even then. The simple reputation of the group would maybe be enough to make affiliated guys "untouchable".