My dogs do very well on a straight meat diet.
Sometimes when people think they are seeing good results, they are good for a time, but the initial benefit may hide a nutritional deficit that takes years to show the damage, and once the liver, kidneys, or other organs are damaged because they didn't get what they needed all along it's irreversible. There are multiple single vitamins and minerals that a dog will develop organ damage from not having access to in their diets.
I had a bird food company that was one of the first pioneers in complete pelleted diets for birds (it still exists). Dog and cat food had been around a lot longer but continually gets better as more research is done on what dogs really need. Dog food manufacturers run into problems with a feed seeming to be great but problems may show up as statistics on dogs over decades can be assessed and analyzed, adjustments to diets constantly get made to commercial formulations.
The benefits of feeding meat comes from the fact that many dog foods have grain fillers, lots of dogs develop allergies to wheat, corn, soy, and other things. Rice tends to be an allergy neutral grain for most animals so it's used in non allergen specialty diets.
There is quite a movement toward making dog food out of meat, it needs to be cooked and grain like rice and vitamins and nutrients added. The problem with this is that the vitamins and nutrients bought as human products will cost you hundreds of dollars and gets into titration issues, or problems getting the micro amount needed because it's in parts per million.
When people start feeding meat they may often see immediate results that indicate a healthier dog, but damage is being done that will cause organ damage, not may be done, is being done. This problem is way worse in breeding dogs, a female that has a litter without the proper nutrients for the puppies growth is going to have puppies that aren't nearly as sound as they would be with proper nutrition, and the mother will decline from litter to litter and the litters will get smaller and the dogs punier. I know people will argue with this, but it's best for a breeder to go a couple of years in between litters. The third or fourth litters will be healthier.
You can say "I've been doing this for however long and my dogs look great". But they will not live as many years and they will have problems they wouldn't have had they had proper nutrition.
Raw game meat, no way. Again maybe you've been getting away with it for decades, but that doesn't mean you will always get away with it.
When I saw how big the idea of making food with better ingredients has become I got the idea a few years ago of creating a complete supplement pre mix for people who want to make batches of healthy food for their dogs, I'm sure there are products available now. People can use any type of meat and we'll do the nutritional breakdown of how much rice or grain and vitamin mix to add per pound.
The advantage we have is that expensive human vitamins are way way cheaper bought in bulk. We get the vitamin mix for our bird food made in thousand pound batches that gets added so many pounds per 40 tons of the pellet mix at a time before it's extruded. We can have an excellent specialty mix of everything needed by a dog that is right for when it's a growing pup, when it's grown, and for breeding females. Buying in bulk it costs a fraction of what it takes to assemble all the human vitamins and minerals. The research correlation involved in studying every research project done on every single ingredient takes a lot of time, my wife has been going to the University library going through research papers for four years now as she's got time and is close to being done.
We are looking to make it to where people can feed their dogs a really healthy diet that they make themselves with quality ingredients. Dog food companies can't afford to use the quality of meat and grains that people are willing to do if they could have the supplements right.
there's some people that believe what they want to believe, and others that are willing to hear what someone says when it's based of reality. I hope this is heard by people who look into it further and have healthier dogs because they heard it.