Exactly. At this point, there's no actual book to publish, just various partial drafts, outlines, and notes. A full novel based on Roddenberry's old script does not and has never existed. Just a bunch of false starts.
And as for having it completed by another author, that's apparently been tried at least four times now--by Koenig, by Sackett, by Friedman, and by Alexander.
Not sure why we'd think a fifth attempt would succeed any better.
So far as I know, none of those people are seasoned writers except for Friedman.