It's unfortunate that some people have difficulty finding clothing in their size, but I feel that there's an undue amount of whining on the subject. I especially think that "fashion" is getting a bum rap in this case.

Fashion might determine what size and shape runway models are, and who and what you'll see while flipping through your favorite trashy fashion mag, but it definitely does not determine what sizes are available in department stores and Victoria's Secret. Stores like this are not so devoted to their god Fashion that they would take a loss by not selling their wares to certain sized people. Plain and simple, they sell the sizes that will be most likely to sell, and those are the sizes which are most common. If you're unusually large or small, you're going to have a hard time finding things in your size. You might even have to pay more for a "special order" item, because you're so "special".

Who are these people that determine what bra size is acceptable?
It's not an international conspiracy against self-esteem, they're called "consumers" and "market forces".