THX 1138 is a Lucasfilm production of a Warner Brothers release, just like Indiana Jones is a Lucasfilm production of a Paramount release, and Star Wars is a Lucasfilm production of a Fox release. This has been the norm with everything except ROTJ and the PT (ESB had a bit of financial support from Fox so they have a better deal).

It's true that some of those aren't top-tier, like Radioland Murders and More American Graffiti, but then most studio library releases aren't either. LFL has Howard the Duck and THX 1138, two cult classics that Anchor Bay would probably gladly pick up if it could, and Captain Eo would be very timely since everyone is about Michael Jackson now (that--and its a really good film). Droids and Ewoks would be bought by every SW fan that buys every fucking Steve Sansweet book. American Graffiti is a classic of cinema, period, that deserves a delux release and that would be immensely popular. Tucker and Willow are good releases too, but the existing DVDs are nothing special (Willow has some features, but I think its actually the Laserdisk video).

The thing is, a lot of these titles have been forgotten--because LFL keeps them locked up! Yeah, there's little demand, but there's little demand because the de-saturation of them from the marketplace takes away their own popularity.