I don't get it. Why exactly is it that we don't add vitamin E and vitamin B if we're doing frankenprey? What in the 80/10/5/5 model makes up for those vitamins? Because after all, they are very necessary.
Taurine, Thiamine, and the Vitamins B and E are a few of the nutrients we know cats need. The knowledge has been gained, for the most part, the hard way. Science hasn't even come close to cataloging all the vitamins, enzymes, amino acids and other nutrients in the bodies of a cat's prey, but we do know that they are completely destroyed with the prey is cooked.
The pet food industry is really just guessing when they add supplements to their heavily processed (and, therefore, pretty much nutritionally dead "food") and it's the consumer's cats (yours and mine) that prove - or disprove - the sufficiency of their supplementation regimens.
Cats have become ill and died from the lack of sufficient taurine and thiamine in commercial pet foods.
The foregoing is fact; the following is my opinion, based off my experiences in the raw-fed world.
People grind and supplement raw food because they are, in a sense, trying to recreate the canned foods everyone is so familiar with. It's more comfortable to the cats - and can certainly be helpful, at least initially, for cats transitioning to raw - and to their owners. Also, it's strongly believed that some nutrients, like Taurine, degrade in the grinding process.
Frankenprey and whole prey raw feeders do not supplement because we're recreating - to a level we find acceptable - the natural diet of our cats. That diet has everything the cat needs, so supplementation is unnecessary and can even be dangerous.
Nutrient profiles differ between prey animals and what is low in one may be higher in another. Chicken, for instance, is high in fat, while rabbit is very lean; quail is high in copper and chicken breast is high in niacin and B6. Since we know we don't know the complete nutrient profile of every animal, we aim for the greatest variety we can get.
Hope this answers your question!