People aren't writing as answers because the only answers we can come up with are subjective, which I think are probably better off as comments. Would you even be happy if people wrote "GameFreak logic" as an answer? Are you asking for our opinions on probable answers? Or are you asking if there is a real answer to this, then what is it? I'm asking because I'm always unsure with questions like this and I'd like to be able to at least know what you're expecting so I can maybe try to help...