It's not just that they can't get them [HD masters], it's that they don't exist. Kadokawa isn't sure where the film elements are either, though I'm not sure they've spent enough time searching for them that they can really be called "lost." Meanwhile MB was trying to tinker with restoring 'em off the old LD masters (which is all that exist right now), but quickly found that they're not very good and not much can be done with them. (We were remarking about how bad they looked at CPM, and look how low our standards were!!)
Not that this doesn't indicate bad things are still happening at MB, but this really wasn't shaping up to be a great release anyway. Not sure anyone will be able to improve much upon the last release CPM did.