The simplest explanation is that the juiciest records were destroyed a long time ago, and released the remaining ones would only lead to speculation and a decrease in trust of the agencies involved.
Because classified records don't always come with expiration dates on their classification status for obvious reasons - even if records are classified for a speficic reason you'd probably want to make sure that reason doesn't still apply ten, twenty or fifty years later. You seem to assume the default is for information not to be classified. The right question to ask is: what incentive would there have been to declassify them earlier?
As others have said, declassification is a process, not a rubber stamp. Declassified records can reference things which are still classified so you need to go through each document line by line and check for such references to make sure they're blanked. Likewise if you want to be particularly helpful you'd have to also go through all previously declassified documents referencing this document and then un-blank their references and republish them, though I doubt that often happens in practice.
You're hoping for a salacious answer. But the real answer is going to be "because declassifying stuff is a time consuming pain in the ass, and no one could be bothered for the file which covered correct letterhead formatting for internal correspondence which technically got sucked into the system 50 years ago and now it's difficult to figure out that that was all it was".
JFK stuff was also declassified under Biden. No one cares because there's nothing in it.
no I don't. I literally said it was a honest question. I truly just want to know more about the underlying mechanisms of why governments classify and declassify things because I don't know much about that.
> JFK stuff was also declassified under Biden. No one cares because there's nothing in it.
A post about it is trending on HN so saying "no one cares" is a dismissal about the interest on this topic. Your very contribution to the post ironically contradicts the content of your message
> saying "no one cares" is a dismissal about the interest on this topic
The point is if you're in a position to declassify banal documents, you probably don't care to do it. You look at them. You see they're banal. You move on.
Never attribute to malice that which is adequately explained by boringness.
A post is trending about the declassification which hasn't actually happened yet. It's not trending about the content of the documents, or even discussing previous documents, in fact no one is even discussing what was in the previous thousands of pages of declassified material.
People care about the idea of the story, not the reality.
JFK investigation documents have been declassified repeatedly, and no one even has any common reference points they bring up about them because ultimately there's nothing there. So this is just the new fantasy: "now, NOW! They'll totally declassify the memo ordering the CIA hit on JFK using mob money and then framing Oswald for it! They've had it the whole time!"
There are lots of interesting / incriminating details in the already released documents. There are also some redacted names which surely would add more context and answer a few questions. I'm sure we won't get many shocking revelations but if they really do release the same documents unredacted that's a step in the right direction.
I remain unconvinced that is going to actually happen, unfortunately. They will present a plan that simply excludes any really revealing documents and what they do release will be a nothing burger. That doesn't mean that there is nothing there, just that they don't genuinely intend to release the goods.