It may just be too expensive to release. There may be all kinds of third-party licensed code in there, and someone will have to go through and audit everything

It may just be too expensive to release. There may be all kinds of third-party licensed code in there, and someone will have to go through and audit everything to find out. If there is some, it'll have to be removed from any external release. ...and if you're releasing a VCS dump, then it's not good enough to just look at the current state of the files: any third-party code that ever got committed will still be there, and will need to be purged. This is going to be a lot of work, and it may simply be infeasible to do so.