restaurants in Italy

Certainly they do, though any solo diner might look out of place. In smaller restaurants there may be something like a community table, a larger table shared by any number of people, a good way to meet people.

Of course. Europe is a great place for solo dining. I do find it is easier to arrive a little early (by European standards) before it gets crowded.

In the larger cities, arriving "earlier" means getting there before 9 pm. For most Americans and Canadians, the bigger issue is that we arrive, eat and are gone before the locals show up for dinner.