Given the nature of protection, it can be argued that supply is more central to an explanation of the mafia's origins than demand, because if the latter can only encourage the former, the former can undoubtedly create the latter. Once a protection market exists, it has a self-reinforcing quality whereby demand is increased by both positive and negative externalities. As we saw in Chapter 1. it is possible to conceive of a state of affairs in which there is no protection and no demand for it either, until an element of protection creeps in and the situation changes to one in which everybody muse be protected . In order to account for the emergence of a protection market, it is not necessary in theory to postulate the presence of exogenously generated distrust and a corresponding demand for protection. The fact that endogenous explanations may be more economical, however, does not imply that they are always true.

XREF: Relates to supply-side explanations in economic theory and how markets can be self-reinforcing, echoing conversations about institutional emergence.

Diego Gambetta, The Sicilian Mafia The Busi…, loc. 846