" If I cannot get all the items on my list at a single store, then I will immediately stop going to that store."

You've got it completely backwards - this new policy is designed for you - the goal is to ensure they always keep product in stock, and the "holes" are a forcing function. Previously WF would just put something else in place, thereby reducing the pressure to restock. Now, the goal is to quickly as possible, ensure they have everything available.