You kind of proved my point there. Is there any evidence that more expensive ingredients are better for dogs?
Royal Canin and Pro Plan are more expensive than Taste of the Wild and other loved brands, they also have the advantage of high volume so where does that money go.
According to a friend of mine who is a feed engineer for cargill (he works on livestock feed but he knows the pet food industry as well) a good part of that money goes to capital intensive research and development. Nutrition is a science and big business and he said they're constantly running studies on their feed and variations looking to improve on outcomes where as smaller companies often outsource analysis and rarely perform controlled experiments on their food once it's approved.
How is it that these brands that are so terrible are the ones with all the prescription diets that vets prescribe to sick dogs.
Your ideas about ingredients sound a bit like people saying why take these distilled pharmaceuticals when we could just consume the a natural herb that contains the active ingredient as well. You can but the fact that it comes as a plant doesn't make it more effective, it usually makes it less.
Here's some interesting reading from a few years back
http://www.dogforum.com/dog-food/pet-food-company-survey-20141/
Here's an example of why I do not trust my vet to advise me on what to feed my dog...
My dog has been having anal glad issues, not it just in the past 2 months became a real problem and my dog is 3 years old, instead of trying to figure out what may be triggering it (I think a combo of salmon and chicken), instead of advising me to increase the fiber in his diet by adding something like oat bran (which I'm doing), metamucil, pumpkin, or something like that, he told me to put my dog on Hill's Science Diet prescription W/D. Here's the ingredient list of the food:
Whole grain wheat, whole grain corn, powdered cellulose, chicken meal, corn gluten meal, whole grain sorghum, soybean mill run, chicken liver flavor, pork fat, soybean oil, pork liver flavor, lactic acid, caramel color, potassium chloride, choline chloride, l-lysine, vitamins (vitamin e supplement, l-ascorbyl-2-polyphosphate (source of vitamin c), niacin supplement, thiamine mononitrate, calcium pantothenate, pyridoxine hydrochloride, vitamin a supplement, vitamin b12 supplement, riboflavin supplement, biotin, folic acid, vitamin d3 supplement), iodized salt, minerals (ferrous sulfate, zinc oxide, copper sulfate, manganous oxide, calcium iodate, sodium selenite), taurine, l-carnitine, calcium sulfate, dl-methionine, l-threonine, l-tryptophan, mixed tocopherols for freshness, natural flavors, beta-carotene
My dog is not diabetic, my dog is not extremely obese, my dog is not elderly, yet I'm told to feed him a food that is basically loaded with stuff his body will not utilize, and will just pass right through him because the food is high in fiber. To make matters worse my vet never even bothered to ask me what I was currently feeding my dog, or if he had any food sensitivities. When I told him my dog does not do well on chicken, do they have a variety with a different protein I was told to feed it anyway and see what happens

I tried transitioning onto it for 2 days, and had the expected result happen, soft stool, so I very happily have discontinued it.