This is a great question as 'ancestral' is certainly the buzz word of the moment and yet it hasn't really come under much scrutiny.
As far as I can see, the question is not so much about whether dogs are best off being fed on the same food as their ancestors (since that is clearly true for all animals) but more about what you define as our dogs' ancestors.
Sure, if you go back far enough, they were indeed wolves and ate a raw, largely meat diet. But that was a long time ago - conservative estimates put it at around 20,000 years since the common ancestor of almost all modern dog breeds was domesticated but some go as far back as 30,000 years or more. With an approximate generation time of 2 years, that means at least 10,000 generations of dog ancestors living and eating with humans!
For all of that time dogs have been eating whatever they could pick up around the human settlements - namely human cast-offs including vegetables, fruits and... brace yourselves... grains!
Add selective breeding into the mix which would have relentlessly favoured individuals that fared better on the new omnivorous diet and you have a strong case for the 'ancestral diet' including more carbs and less meat and being at least partially cooked.
From my experience, both versions of the ancestral diet can work exceedingly well, even for the same dog so it's not necessarily a case of either/or. And for more sedentary dogs, high meat/high protein/high fat foods can still work wonders as long as you feed less.
The approach that certainly doesn't work is adding ingredients that none of our dogs' ancestors (at least prior to the invention of complete dog foods) would have ever come into contact with like wheat (modern common-wheat at least), refined sugars, chemical colourings and preservatives, vegetable protein isolates, added salt and so on. Unfortunately these are exactly the same ingredients that have become the staple of Big pet food.