One of the explanations that I have managed to give is that Sardinia, although not poor by any standard, was never as rich of resources as countries like Sicily.
This key difference caused a huge divergence in the development of the two islands. In Sicily there were greater rewards to be ripped from controlling the resources of the land: families that could get access to these resources had greater incentives to safeguard their control over them, using violent and coercive methods when necessary. This control of the economic resources by few powerful families had to be guaranteed by exclusive political institutions, and the story of the Mafia is full of examples of Mafiosi fighting against attempts to create more inclusive and transparent institutions.
On the contrary, in Sardinia there were less incentives to gain absolute control of the resources of the land. Furthermore, for long periods of its history, Sardinia was controlled by far away authorities (the King of Aragon, the Emperor of Spain): once they gained control over the few profitable resources (e.g. mines and quarries), these rulers had little interest in gaining total control over the rest of the island economy. This granted Sardinians some degree of autonomy, and Sardinians developed more inclusive economic institutions (for example, villages in Sardinia used to share their land between villagers).
This inclusiveness has historically generated a work ethics that is quite different in comparison to that of other Mediterranean countries. Sardinians tend to value hard work and thriftiness. This may help explain why sometimes I think about Sardinians as closet-protestants of the Mediterranean: the work ethics and the thriftiness of Sardinians often is embodied in austerity and sternness that are usually considered to be characteristics of the Presbyterian Europeans.
I believe that Sardinian history of inclusive economic institutions and the work ethics it generated could be translated into institutions that could help create prosperity for the people of Sardinia. The current economic and political institutions in Sardinia have been hijacked and have become exclusive and extractive, i.e. interested in extracting resources and income for a restricted group of people. However, the recession that has marred the whole of Italy and the increasing dearth of economic opportunities, particularly for young people, has contributed to generate increasing discontent and a desire for change and inclusive institutions.
Unfortunately, this discontent has been so far captured only by the populist Five-Star Movement, which, despite its lip-service to openness and inclusivity, does not seem to have a credible and serious agenda for creating liberal and inclusive economic institutions. On the other hand, the nationalist parties in Sardinia seem as yet unable to engage in a credible program of institutional reforms, and seem too preoccupied by identity politics (rather than bread-and-butter issues).
This is a pity: in the long run, the current extractive and exclusive economic and political institutions could eradicate the Sardinian work ethics and thriftiness, and eventually hamper any hope of a positive change for the future of Sardinia.
