Cold brew takes more refrigerator space, which is relatively inflexible. Since it brews overnight, you have to put aside enough fridge space for all the cold brew you expect to sell that day. Contrast with regular coffee, which you make largely on-demand, with only the coffee beans to store overnight, on a shelf. So raising the price might be the sensible thing to do, to discourage purchases and/or pay for the extra refrigerator space.
