I would like to point out that not only is home video expensive in Japan... The first series of Pocket Monsters never even got a home video release. Later series at least have the episodes available for rent (which, given Japan's steep prices for DVD and BD, is actually far more accessible to your average viewer), but the Kanto arc? Nothing doing, you flat-out can't get those episodes on DVD. Though they are available for streaming on Amazon and Netflix, so... yeah, actually it's not at all difficult for people to see them if they want to. This movie is really just a milestone celebration, going back to the beginning of the story to celebrate 20 years of the anime, and branching it off into its own plot which might perhaps, if we're lucky, mean that we will have a version of Satoshi's journey that has an ending. ...while throwing in a few new Pokémon because they gotta advertise Sun & Moon I guess.