I think you underestimate the human ability to ignore that which challenges our world views. I've known people who loved their dogs but still felt that their dogs didn't experience the world, only acting as if they did. Not just that the dogs lacked self-awareness or something, but that the dogs did not experience anything, because they don't have magical metaphysical souls like we obviously do. I've known these people, and discussed this topic with them at length. If somebody can have a loving relationship with a social animal and still feel this way, I have a hard time believing that spending three years with a significantly more intelligent non-human animal would necessarily change their mind.