That all sounds good in theory. But the reality is, all breeds come from the same stock that in the wild eats essentially the same diet. That would be prey — including "4D" meals of the dead, dying, diseased, and disabled. Their health thrives on such foods.
Thus, the positioning of commercial diets as "breed specific" is done to create a marketing niche and has no basis in scientific fact. Even cats and dogs naturally eat the same foods. Yes, the feline has certain needs that exceed those of a canine (higher protein, taurine, vitamin A, etc.) but that would only be important if a food is formulated to achieve minimal nutritional levels. If the diet is varied and includes whole natural ingredients the animal would normally eat in the wild, such individual nutrient concerns vanish.
The proper goal for health, therefore, is to seek maximum optimal nutrition, not tailored diets that presume to know how to shuffle individual nutrients.