For some reason, I always thought that the Heinz "57" referred to herbs and spices or the number of ingredients in the ketchup. I can't find a current list of products because they vary so much from region to region, but I bet there are more than 57 these days. Just not in every state.
Which, I think, suggests something good about the state of the food industry - that they customize and regionalize so local flavors and preferences are preserved. Then again, the differences might mostly be in marketing and they might be economically-driven, not forced by taste preferences. But who knows, besides the Heinz marketing team?