because people don't know what pizza is so they'll buy anything labeled Pizza so long as it has cheese, sauce and bread.

Most people don't even know the regional difference in styles of Pizza, if you ignore their inability to identify it in the first place.

You have New York Style, Deep Dish, Nebraska Style, Pan, St. Louis Style for instance. New York style is that giant pizza with a thin layer of sweet sauce, and you have to roll it a bit to eat it. Pugsely in the Bronx is the best in my opinion.

Deep Dish isn't "Chicago style", but similar in idea. It has a lot of care put into a thick-bowl like buttery crust, a layer of sauce, a layer of cheese and smothered in toppings. Again the sauce is sweet, but it's thicker, and has other flavorings added. You can find it all over, but the one i did like wasfrom Detroit.

St. Louis style is a thin crust, almost cracker like, buttery, with the thicker sauce found in Deep Dish Fortel's and of course Imo's shoutout here for you cardinal fans.

Pan style and Nebraska style are similar, but Pan is notable for having no notable features and no one way to describe it other than its what you get at Pizza Hut and Domino's.

Nebraska Style though is my favorite. It has a thicker, flakier buttery crust with a distinctively sweet sauce, thinner than St. Louis, but more flavored than New York. It often times swaps the Toppings underneath the cheese - this helps keep the toppings flavor (or so ive been told). Godfathers is a chain that does this well, otherwise Valentinos if you ever are so unlucky to end up in Nebraska for any given reason. It's a chain as well, but almost all the mom & pop pizzerias do it right.

Chicago Style is a casserole.

tl;dr: Because people stupid about pizza and buy things labeled pizza