It's probably also that the mentality of today's criminals has changed, deeply rooted in the south there still will be Omertà like in the case of Messina Denaro. But it isn't as strong as it used to be.

Sicilians adopted the code long before the emergence of Cosa Nostra, and it may have been heavily influenced by centuries of state oppression and foreign domination. It has been observed at least as far back as the 16th century as a way of opposing Spanish rule.