A question: is my impression correct or not, that the mafia was often involved in heists mostly just at the beginning of the century? It seems to me that robberies and thefts are more typical of relatively small-time criminals, while racketeers and mafiosi prefer semi-legal methods like extortion which can make more money anyway and is harder to prove, since the victim can always say "it was a completely voluntarily contribution to my business partner".
For example, in Sicily the zones with a large number of thefts are considered ones with weak mafia influence, while robberies were often committed by the Stidda but rarely by Cosa Nostra, as far as I know.
Of course, there were exceptions in later years, like the Lufthansa robbery, when it was especially lucrative.