I've worked at multiple chain places and the cheese is definitely not the same everywhere. Smaller chains usually use Sysco for distribution and they have a whole collection of like 30 cheeses to choose from. Some use more bespoke "Italian food" distributors that specialize in meats and cheeses that are absolutely not all the same.
The big 3 all have their own distribution networks too. Papa John corporate isn't in the business of selling pizza, they're in the business of selling dough, black olives, and cheese to their franchisees. Same with Dominoes and Pizza Hut.
I've worked at multiple chain places and the cheese is definitely not the same everywhere. Smaller chains usually use Sysco for distribution and they have a whole collection of like 30 cheeses to choose from. Some use more bespoke "Italian food" distributors that specialize in meats and cheeses that are absolutely not all the same.
The big 3 all have their own distribution networks too. Papa John corporate isn't in the business of selling pizza, they're in the business of selling dough, black olives, and cheese to their franchisees. Same with Dominoes and Pizza Hut.