How can I increase my dog's interest in his kibble?
Change how your dog sees their food! The reason dogs love treats is not only the taste but rather how we present each piece to them.
Make use of food puzzles, snuffle mats, fun/challenging new toys and your dog's walks to provide them their kibble, instead of their bowl. Most dogs are not interested in their dog bowls because they don't meet a core need of a dog which is to have to figure out, search, scavenge and hunt for ways to find and get to each bite!