you know how it is when you've tasted something nice, then ask the person who prepared the food how it's done - you'll be told the ingredients & the method of preparation, & when you do it yourself, it doesn't taste quite so heavenly?
presumably, there may be a important ingredient or crucial technique which was never revealed in the 1st place? after all, not many people are willing to share their prized dish with others, or else, it won't enjoyed its uniqueness.
so when i read that the secret ingredients of coca-cola has finally been revealed (read here), i sniggered to myself because i doubt the authenicity of the secret. besides, the technique of preparation wasn't revealed, so it may be many, many more years before anyone else can come up with an identical brew. i mean, have you tasted tesco's cola??
similarly, whatever spices people think they can guessed from the colonel's recipe, no one can quite fry chicken like KFC. if we could, KFC would have closed down long ago.
it all boils down to the personal touch.