It’s easy to get confused when thinking about Outtakes and Demos as they are part of any song production process and each go through many different takes, versions, arrangements and iterations before being release.
In 2004 I discussed the definition with Jim Vallance, a famous multiple award winning song writer from Vancouver that is also co-writer of several Aerosmith hits, this is was he had to say:
“A ‘demo’ is usually a rough recording done in a home studio. If the band likes it, and the producer likes it, and the record company likes it, then the song gets recorded in a “real” studio, at which point it’s considered a ‘master’ recording. If, for some reason, the master recording is not completed (vocals not finished or something) or it’s not released, then it’s called an ‘out-take’. Basically, outtake means not used”.Jim Vallance via email, 2006
There are myriad of reasons why these songs are not released and I don’t know whether they will ever be released. It’s really up to the band and their various labels. All I can say as their A&R person is that most of them were not released because they were not good enough.John Kalodner via the Ask a Question section of his web, 2005