Yeah, I sincerely doubt that people didn't exagerate the recording sessions.
Actually, there are more things to take into consideration.
1. Exagerate for PR, since he wanted to keep his "untouchable" image. If you ask me, he might have had some psychic issues such as OCD that led him to make some questionable decisions, but this is not the point. Even though he could've ended some of the rumours regarding him during his lifetime, being misterios was a better PR stunt than addressing them with proper proof. (e.g. marriages, children, health problems, choosing to settle for the 1993 allegations, wearing mask and sunglasses in public - even though it was pretty easy to guess who he was - )
2. He might have written them, but didn't record them or are in a very rough state. (let's take Pop Smoke for example - young rapper that died 2 years ago - his estate released EVERY snippet they could from the vault along with his "biggest" hit on both of his posthumous albums. What did the fans get? 3-4 rough demos merged into one song along with features to completed the song on almost every track. I think to merge songs like HT or IATL and APWNN + a guest feature from some current hot shot like Harry Styles would be cringe as hell). As rough demos we have the WBSS/Beat It/Billie Jean demos from 81. In case of concerts, for Thriller there would obviously be discussions with the J5, so a deal between them is improbable IMO. The 2001 concert from MSG was a once in a life time chance for both of the parties to come together.
3. There might be issues with the people that were linked to the production/recording/mixing of the song. (royalties pay really low, especially in the streaming era, I understand why some producers keep the songs from themselves and chose to go to interviews/have seminars instead of giving them to the Estate. It pays better. I don't buy "It's all for love. I don't want them to touch my songs" bs especially since they decided to showcase the demos along the remixed versions). We have Quincy, who was the main man during the OTW/Thriller/Bad era. If they are on bad terms, I don't expect songs to be approved for release, even if they are in the vault. As morbid as it sounds, some years might have to pass until those who inherit the rights will want to give their approval for release. Or like Will.I.Am who was this forum's golden boy in 2009 for not wanting to give the Estate the instrumentals he worked together with Michael (the Estate has the vocals). In the end he just wanted to release the tracks on his album later, like the greedy scumbag he is. The Estate said no (obviously) so he released some of the songs with his own vocals. Not gonna comment on his quality of production, it's not usually my type. But all in all, he is part of the Thriller legacy with 2 remixes on T25 and I am not. Michael liked his work, even though he allegedly hated remixes, but released 2 of his on T25 instead of some unreleased tracks for the fans. As I said earlier, questionable decisions and PR stunts.
4. Michael was a mess when it comes to being organised. I can't give you the exact source, but I remember reading around here that he forgot about masters of his filmed concerts (which kinda connects to them having only limited material stored on film, e.g. APOM video from the BAD25 docu). So if he was negligent with the concerts, I'm pretty sure there wasn't a difference when it came to songs. It's just that more people had a copy of the songs in this case (engineers, producers, writers). This is where having different mixes for the songs comes in place (I think). I remember him being mad in 2003 for the Escape (song) leak from one of the studio engineers. So keep the faith folks, we might have some undiscovered pre-album mixes of different songs. We also have LaToya(?) allegedly walking out of Michael's house with some hard drives with his work? Dunno what happened to them. But my point still stands. He was totally all over the place with everything he created.
With all this in mind, I'm not saying the Estate is perfect. They made mistakes. There are worse Estates there (e.g. Pop Smoke), or better (e.g. Elvis, Prince), but strictly speaking in this case, I wouldn't want to be in their position of decision making.
