Diversified occupational groups spawned the specialized protection industry.

Evidence

In other conglomerates around the time of Unification, occupations were more varied (Lupo 1988; Pezzino 1989a). It is in these more diverse groups that I believe the protection industry actually originated. Each member counted on the group as a whole for reputation and support and then acted as guarantor-protector in a cartel arrangement. Thus, the mafioso protecting millers, whether or not he was a miller himself, was also part of another group, the local mafia, which incorporated people involved in different occupations who provided the same service. — Diego Gambetta, The Sicilian Mafia The Business of…, 221

Categorization

• XREF: The move from occupation-specific cartels to a cross-occupational group providing protection is the structural origin of Gambetta’s private-protection market — exactly the mechanism the reader is mapping onto Vendetto/Capone-style state-failure enforcement.
• SEED: A potential article: how diversification of a trade guild produces a shared-protection service that eventually outgrows any single trade — the point where a mutual-aid society becomes an industry.