Recipes are in many ways the least important part of what a chef provides. They're not secrets. If there's a "secret ingredient" it's that they're using more butter and salt than you'd use at home.
What a chef provides is a process. They get the ingredients ordered, at the quality level they want for a price they're willing to pay. They ensure that the ingredients show up, in the amounts needed, without waste and without falling short -- and have backup plans. They staff the kitchen, and ensure that they have all prepared their stations before service begins. They train the expediter to ensure that all of the food comes out together, without things waiting under the warmer.
The chef also provides a menu, which is more important than the recipes. It has something for every guest, and every item can be finished before the guest gets impatient.
It's not impossible for a business guy to hire a top-notch executive chef to do that work, but the business guy cannot do it. It requires years in the kitchen to know what factors are important. It requires a deep understanding of the culture of kitchen workers, and how to get the best out of them. It would require an enormous staff to do that properly, and training them extremely well.
You can see this at work at a place like The Cheesecake Factory. It's hardly great food, but it's reliably good. The menu is enormous, on par with a dozen restaurants at once. It can be done. You're just not going to do it Silicon Valley style, learning as you go.
