While converting from .sup to .srt can be a pain, its more tedious than difficult. It seems several movies over the past few months have had non-english dialog in an otherwise all english movie, these types of subtitles can be converted quite quickly. Even a movie that needs to be done completely isn't that bad once you start teaching the OCR how to identify each letter. Its movies like Tora! Tora! Tora! that make you want to pull your hair out. For an english speaking viewer, half the subs need to be removed (english speech) and the other half need to be converted (japanese speech). You have to be watching the movie and converting at the same time.
By the time I finished this movie, it will probably be another 20 years before I have an interest in watching it again.