Best guess is no American company was interested enough. Or maybe there was some other issue, but most of it was probably money rather than legal issues with rights holders since that doesn't seem to be an issue even if there is talk of a Star Blazers live action film from time to time.
I know that there are English subtitles from Hong Kong, Singapore and Australia.
Reportedly the main actor's contract did say something about his voice not being dubbed over, but I guess the Spanish and Germans don't care about that. Perhaps it is an English only thing.
I know the Japanese BD will work on an American BD player, but doesn't have English subtitles for the live action movie.