Disney produced The Black Hole in 1979 for the same reason that Paramount brought back Star Trek and the same reason that Ion Productions made Moonraker their next James Bond adaptation, because two years previously a little movie called Star Wars came out and changed the world.
Everybody had to make a science fiction movie and The Black Hole was what Disney did.
But as Jon Spaihts tells Slashfilm, Disney doesn’t really need their original space epic that competed with Star Wars because now they actually have Star Wars for that.
On top of that, they have The Guardians of the Galaxy coming from Marvel in case they feel like they need more sci-fi.