> Later franchise shows that were shot in digital simply cannot be released in HD as there is no HD source material.
This is a persistent myth, but false. DS9 and Voyager were shot on film, like TNG and TOS. TOS was also edited on film, TNG and later were scanned and edited on videotape. This makes it much more work to remaster TNG and later shows for HD, which was done for TNG but not later shows because the TNG sales plus the perception that the other shows wwre less popular and would sell less made it not worthwhile from a business perspective.
This is a persistent myth, but false. DS9 and Voyager were shot on film, like TNG and TOS. TOS was also edited on film, TNG and later were scanned and edited on videotape. This makes it much more work to remaster TNG and later shows for HD, which was done for TNG but not later shows because the TNG sales plus the perception that the other shows wwre less popular and would sell less made it not worthwhile from a business perspective.