Nobody Knows Anything
Goldman’s quote is true of publishing as well. There are no guarantees, just gut feelings and gambles. Editors and publishers know what worked before. They have theories on why it worked. But they can’t be sure the same thing will work again. They can’t be sure that the exact opposite won’t.
Anyone who tells you must/mustn’t, have to/can’t, is sharing an opinion. It may be an informed opinion based on experience. It’s good to listen to experience. But ultimately, your writing is your art. You have to decide.