I don't know where your from, but in the supermarkets I go to they have white bread aswell. But I do tend to notice, it's usually the tuna sandwiches that come with brown bread and chicken and stuffing comes with white bread.
To me, sandwiches are something you make yourself - I've never bought pre-made ones. (And then I can choose the bread...wholemeal or granary for preference).
Make your own - cheaper and more delicious....here for lunch today, fresh white tranches of a local bakery bread, a vine tomato cut up, a little watercress, 1/3rd of a camembert sliced, a turn of black pepper and then toasted in a pan with butter and a little oil..... cost c. £2.00 for two large sarnies.