OK, come up with some links proving dogs are healthier eating foods with high ratings at dogfoodanalysis.
Suppose you knew a breeder that bred hundreds of dogs a year, mostly Labs, Shepherds, and Goldens. They provided all the medical care for most of them the first year. At the end of it, they did a complete physical including hip X-rays on all of them. They then spent $35,000 training them before giving them away. They have a large data base of breeding records. Dogs with any physical or temperamental problems are unfit for the program and are a waste. Their well equipped clinic and vet staff are available for serious problems as long as the dog is working. When the dog is no longer able to work, it is replaced at again the $35,000 plus a large emotional upheaval for the person depending on the dog. They have experimented with different diets and exchanged data with other such breeders. Don't you think that what ever they are feeding is healthy and safe? What kinds of controlled studies do you have backing your choice of diet? How objective are the sources of your information? Is your dog's health, their top priority?
I have been raising puppies since 1991 for a large dog guide school that does exactly that. What do they feed? They instruct us to feed Pro Plan chicken and rice puppy chow until 4 months and then switch to adult Pro Plan chicken and rice. I know enough of the people with the trained dogs to know they continue the Pro Plan. The group I meet with monthly for training includes people that have raised puppies for 6 different service dog schools. Some of them are feeding other common commercial chows including Iams and Eukanuba. Any dog owner wanting a healthy, long lived dog can make this regimen work, leaving more time to spend on the dog. It is also relatively economical.