On the contrary, after having lived in Rome for several years, I can say that the OP's scenarios are not at all in the realms of fiction.

Many of the stories came from Italians rather than expatriates - so probably give more credence to sceptics. The OP didn't mention the Vespa-rider-stealing-handbag-from-passing-pedestrian, for example - happened to a colleague of mine.

The Italian police just don't want to know. There was a famous article in The Economist in the late 1980s (things don't change!) where one of their reporters who was robbed in the street and had the registration of the car involved except for the last digit, went immediately to a police station. The police did nothing for two hours (said reporter saw them watching television in an adjacent room). When this was exposed in an article in The Economist, the Italian press claimed it couldn't be true because the reporter "refused" to give his name in the article. [The Economist had a strict policy of not naming its reporters].