Your local coastal city store might have a half dozen plain greek yogurts but I bet there are plenty of areas where they are not stocked because they know it won't sell.

But hey, don't take my word for it. Most large supermarkets now offer online ordering. Pick a few small Midwestern cities at random and look what dairy products the major local supermarkets have in stock. It's hilarious how people keep posting uninformed comments here without taking 5 minutes to do some trivial fact checking.