If memory serves me right, Italy was one of the last countries to unify its states. Because of the many dialects of the Italian language, radio and television personnel were taught Italian as spoken in the richest community, Rome. Most Voice Teachers teach Radio/Television Italian. The problem: Dialects. No one recorded spoken Italian in Mozart's time. Many singers imitate Italian. Opera Houses do not have rules of pronunciation. Singers don't study John Moriarty's book, Diction.
There was a mistake in my post 28 to 57 for women. These numbers need to be revisited by the experts.