Simple the South Italy was always poor and before the 1980s the Italian State wasn't more present and in some areas the ndrangheta,camorra,mafia or Sacra Corona Unita are the other state that control the territory,can find you a job and so on plus if a clan die suddently a another clan take his place with an other names but is the same shit.
In some areas there are a refuse to the state even with the language that is the dialect and not the italians,the couples make sons at young age in some cases under age because the boys know that they risk to die young and watch the 30 y old like the other people look at the old men.