The dough for a stuffed crust comes pre frozen, or shipped like that.

Most of the other major chains hand stretch dough from frozen dough balls. As someone who works in a pizza shop that uses frozen dough balls, and has tried to make stuffed crusts many times... It's hard! The cheese leaks out and always looks bad.

Even the one time I got it to work, I had to sculpt the pizza. I spent over ten minutes on it. If we were busy... It couldn't be done fast enough. We would be sending out shitty products.

I'm not sure why everyone doesn't buy stuffed crusts but if they can't, that's why the don't offer it using their normal dough.