Here's the thing, they are making dozens, even hundreds of the same dish, every day. They are going to become intimately familiar with how it's supposed to be. This is on top of having created similar dishes tens of thousands of times already. That's their job. I have a different job, but I still want to make good tasting food home and I only cook a few dishes a day. As a technical writer, I know that having document that both a novice and an expert can access easily is a hard, hard problem. It's doable but there are so many traditions around cookbooks it's hard to get around them.