My personal suspicion is that most dogs can thrive on a wide variety of diets, and that while any particular diet may be superior for an individual dog, that there isn't a blanket "better" diet for dogs as a species. I also suspect that for most dogs, even if one diet was "superior" to another, the degree of benefit is probably be negligible most of the time. I think other factors like the amount of exercise a dog gets and staying at a healthy weight have more of an impact than what the exact diet is for most dogs.
Kim is one of those exception dogs. Mira would thrive on any decent quality food so long as there is a lake involved