[toyg]

I would take what a "Austrian-born Hindu monk and professor of Anthropology at Syracuse University" says on the history of a traditional staple of my own country's diet with a massive grain of salt.

Pizza existed before Italian migration to North America was even a thing. It gained tomatoes when they became more readily available and better known in the early XIX century, and that's about it. The explosion in Italian migration happened later, by then most of the traditional pizzas had long been codified.