That's not obvious to me. Can you elaborate?
https://www.youtube.com/watch?v=eZHsmb4ezEk
(in particular, note how it calls attention to the importance of —asymmetric!— ritual gift exchange for vertical ties)
(and Barzini's presence —depicted due to the photographer, a little later— demonstrates horizontal ties among the Big Men)
Of course, these institutions also change and adapt to competition with the state—for instance, when the state tries to break up the mafia using the literal prisoners dilemma, the mafia needs to invent and enforce the institution of “snitches get stitches”. More troubling is when pre-state mechanisms of dispute resolution can be end-run by disputants trying to enlist the state on their side. For instance, the notorious Hatfield/McCoy feud was exacerbated by various prominent members of one clan or the other getting themselves elected sheriff and abusing their power against the rival clan.
compare https://en.wikipedia.org/wiki/Systems_of_Survival#Descriptio...
they're using game theoretic payouts, but it's not the literal "prisoner's dilemma" which has it in each prisoner's interest to rat no matter what the other prisoner does, and yet it's still net advantageous for neither to rat.