He approved the release of many demos and unfinished recordings, while he was alive, on releases like "The Ultimate Collection"and the 2001 reissue of his classic albums.
As I have said in my previous post, he approved of the box set in 2004 because he wanted his contract with Sony to end. He himself called the project 'just a box set with two new songs on it', so it was not a project which he made because he wanted to, but because he had to and did not care at that point what they were releasing, as long as his contract with them would end after that.
It's also extremely questionable how much he cared about a box set they were releasing when he was just about to have his trial in a couple of months, but anyway.
If anything, the 2001 reissues of his albums prove my point regarding his dislike of releasing unfinished music. Let's take a look at the bonus material:
Off the Wall (2001 edition): You have nine tracks,
seven of which are portions of interviews with Quincy Jones and Rod Temperton. The only 'new' songs are the demos of
Don't Stop 'Til You Get Enough and
Working Day and Night - two songs which had been released officially. So, no new songs from these sessions.
Thriller (2001 edition): There are twelve tracks and only one demo, which is the demo of
Billie Jean, a song which was released, and one unreleased song, Carousel. The song Carousel is not a demo, but a finished song. In fact, the song was scrapped from the album at the last minute in favour of
Human Nature.
Bad (2001 edition): Here again, out of the seven tracks, we get two new songs:
Streetwalker and
Fly Away. The former is, once again, not a demo. It's finished and it was, like
Carousel, scrapped at the last moment in favour of
Another Part Of Me. Michael's version of
Fly Away appears to be a demo, however, the song had been released by Rebbie Jackson in 1998, so you can't call it an unreleased song.
Dangerous (2001 edition): Not a single new song. And there were so many to choose from.
The original plan for Thriller 25, was to include many of the demos which are now circulating online. However, Michael rejected this idea and instead we only got these remixes and
For All Time, a demo from the Dangerous sessions. In the book Remember The Time, Bill Whitfield wrote that there were many plans for Thriller 25, but Michael wasn't interested in them.
The conclusion is that Michael was never enthusiastic about releasing any unfinished material to the public. Every time he did it, he had to do it.