What defines something as pizza is the base, not the toppings.
Of course there are some common and more classic toppings, but those include also no cheese pizzas
The base is bread. The pizza is defined as the base + cheese + tomato sauce + various toppings.
a dish of Italian origin, consisting of a flat round base of dough baked with a topping of tomatoes and cheese, typically with added meat, fish, or vegetables.
What defines something as pizza is the base, not the toppings. Of course there are some common and more classic toppings, but those include also no cheese pizzas
The base is bread. The pizza is defined as the base + cheese + tomato sauce + various toppings.
Source: the dictionary.
The base is not bread. Even your definition doesn’t call it bread. It’s pizza. And a random American dictionary is hardly a source.
Also, pizza is older than tomato in Europe…
Here’s an Italian dictionary, if talking with an Italian wasn’t enough
https://www.treccani.it/vocabolario/pizza/