They make the food laws

As of 2023, the global pet care market was estimated to be worth a whopping $246.66 billion and is project to reach $427.75 billion by 2032.  Approximately $147 billion was spent on pet foods and treats alone.

Mars Inc. and companies like it, including Nestle Purina, Hill's Science Diet and General Mills own the dog food market and are in business of profit, and not keeping animals alive or well.

These are the same companies that essentially regulates itself by working closely with an organization called The Association of American Feed Controls (AAFCO).   The AAFCO is a voluntary regulatory organization that sets the standards and requirements for every dog food in the USA and determine if a a given company's claim for "nutritionally complete" foods are legit and have the authority to hold companies accountable for misinformation and control labeling, ingredient, and nutritional requirements.  

Members of the organization are mostly local, state, and federal government officials whose work concerns animals, food, and other related industries.  Many of their members are also employees of big kibble companies, such as Cargill Animal Nutrition, Elanco, Nestle Purina, Hills Pet Nutrition, Blue Buffalo, Mars Inc., 

With this close collaboration, kibble manufacturers are allowed to have a significant hand in regulating their own products.  "Companies who are legally allowed to play by their own unchecked rules are not working in the interest of their customers or their dogs" (Source: Maev)