Actually they are not. "Practically" is carrying a lot of weight there. The factory baked cake will have a lot more extraneous ingredients and usually has a larger quantity of sugar and fat. Similar to how restaurant food generally has a lot more salt and fat than home cooked food.
It's easier to waive cost overages than deal with any of that.
And why is that a problem? And how different is that from "forgetting" to pay your bill and having your production environment brought down?