This is a really touchy subject for me and a lot of Pokemon Anime fans, since I prefer watching Pokemon in Japanese (not saying that the English Dub is terrible, it's pretty decent, but I just prefer the Japanese version more), but it does come back to the fact that it's too niche.
It's comes down to the fact that Pokemon's target audience is primary children and young teenagers who want to watch the show in English since they don't want to read subtitles. This will mean that if The Pokemon Company releases the Japanese version of the show on DVD/Blu Ray, they will probably make a loss since the only people who will buy these releases are older fans like us (people in their mid-teens to adults), since casual fans will pick the dub and non-fans will pick the English versions since they don't want to read subtitles and nostalgia. But, at the end of the day TPC is a business and a businesses main goal is too make as much profit as possible, so if they predict that something will make a loss (like with a hypothetical release of the Japanese Version of Pokemon), they won't go through with it. Since they would want to have as many episodes available as possible, it will take a lot of human resources and production costs to bring this idea to life.
I think that The Pokemon Company should make a deal with Crunchyroll in order to have simulcasts of the anime on their service, along with all of the past episodes on there in order to please fans since I predict that a release like this will be successful. I use Crunchyroll for basically all of my anime watching and Pokemon is the one show that I watch on Pirate Anime Sites since it's the only way to watch new episodes (along with the very few older episodes that are available) and I feel very guilty since I know in the back of my head that the people who made this episode won't be getting paid for my viewing, which makes me a little bit sad.
Going back to the Crunchyroll part, I know Netflix has the entire XY/XYZ series, the 3 XY Movies, SM up to the Kanto Arc (up to Episode 43) and the first 52 episodes on the Kanto anime dubbed (this is on Netflix UK, not sure about other countries). They seem to be pretty popular and I've only put this last bit in to prove that my Crunchyroll idea could work, since the dub is doing well on Netflix, a family orientated service, while Crunchyroll is more aimed towards Teenagers and Adults who watched subbed anime anyway, so I feel that it will also be successful.