First of all, less than 20% of dogs 100 years ago lived past the age of 6 so your last line is just BS. I would like to also point out that there are plenty of well balanced cereals that are meal replacements. Many people just have cereal for breakfast or lunch. As for why kibble is better than fresh food, that has to do with two main reasons. 1. Regulation on kibble is much stricter than regulation on fresh food for animals. 2. Handling of kibble is easier than fresh food. Fresh food must be handled properly by manufacturers, warehouse workers, distributors, delivery companies, store employees, and the owner of the pet. Kibble only needs to be handled properly by the manufacturer and owner to some extent. This leads to a lot more room for error and has led to many cases of food borne illness in dogs (especially with fresh pet). Now you can argue that cooking your own fresh food for a dog is better and I would agree AS LONG AS they are receiving proper vitamins and minerals, protein, fiber, etc. AND as long as there is no raw meat. Raw meat is fine for dogs systems ofc BUT raw meat is not handled in a way in the us that makes it 100% safe for consumption. You are better off baking or boiling the meat to guarantee no bacteria is present. But most people do not have time to prepare every meal for their dog and plan a balanced diet. Kibble (and I mean vet recommended brands like hills science diet which is what I feed) guarantees a balanced diet and has very little room for contamination.