The answer is they want to.
There are factions within the US government and it seems that the "tell them, but take it real slow" faction is presently in the ascendant.
You seem to be leaning toward an extraterrestrial explanation. I'm not saying you are definitely wrong, but it seems like a very low probability explanation and one that defies the principle of parsimony.
They have been sitting on this stuff. They still are sitting on 99.9999% of it, is a reasonable assumption. They are choosing, deliberately, to gradually change attitudes. Part of the gradualness is maintaining intentional levels of ambiguity that can be slowly, slowly dialled down.
All of this is kind of orthogonal to what they are sitting on. Doesn't have to be ET.
Link? Who are these people? Are they credible? Do they seem rational, reasonable, and (highly) skeptical?
> They still are sitting on 99.9999% of it, is a reasonable assumption
There is nothing reasonable about this assumption.
> All of this is kind of orthogonal to what they are sitting on
Huh? How? Why?
This is all veering into conspiracy-theorist-cum-crackpot territory. You are doing some extreme extrapolation from very thin and inconclusive evidence.
Decommission the internalized cover up ("If you see a UFO you are a kook and will lose your job"). This gets in the way of receiving useful intelligence reports.
(Partially) decommission the external cover up, at least enough that the public sees UFOs as a known but unexplained phenomenon. And as military business.
Paradoxically, cover up the cover up itself, by acting like all this stuff is new to them and hasn't been under observation since the 1940s.
Obtain funding due to the public not liking UFOs poking into their airspace without permission.
Bring technologies out into the mainstream, commercially or militarily. Looots of funding.
It feels looking in from outside, as if there are "pro continued cover up" and "pro managed disclosure" factions, and they are in a bit of a stand-off. The recent disclosure that the videos were genuine, for example, felt like the one faction had bought the release of that shocking information with the apologetic concession that "but they were never meant to be released to the public" which was included in the same statement.
That somebody on the internet (or an organization full of cranks like TTSA) can say they watched the "full video", and you don't even question it, is telling. Unfortunately this, like the entire recent narrative of some sort of a "disclosure", seems more like a fantasy invented by UFO enthusiasts that really wish it to be true, than something based on reality.
* https://www.metabunk.org/nyt-gimbal-video-of-u-s-navy-jet-en...
* https://www.metabunk.org/are-the-navy-ufos-real-or-just-in-t...
* https://www.metabunk.org/nyt-gimbal-video-of-u-s-navy-jet-en...
* https://www.metabunk.org/ttsa-videos-declassification-email-...
This echoes the 2013 Aguadilla Puerto Rico UAP/USO incident:
* Aguadilla Infrared Footage of 'UFOs' - Hot Air Wedding Lanterns
https://www.metabunk.org/aguadilla-infrared-footage-of-ufos-...
... While "real," those videos in fact show (as the Navy must be well-aware) easily explained FLIR artefacts; e.g. distant jet fighter exhaust ports. Wittingly or unwittingly, the US Navy / TTSA / Elizondo et al. apparently are part of an elaborate, ongoing disinformation campaign.
----------------------------------------------------
* $21 Trillion Missing From US Federal Budget
https://www.globalresearch.ca/21-trillion-missing-from-us-fe...
Military-industrial complex / "threats" / USAP black budget funding:
Communism | Cold War >> asteroids (SDI) >> war on terror >> AATIP (Advanced Aerospace THREAT Identification Program): unexplained aerial phenomena? >> Oh no! ETI threat!! >> $$$$
https://www.youtube.com/watch?v=Eco2s3-0zsQ&t=35m50s
[A cube floating into a spherical force field]
It made me thought of Salvatore Pais other patents on the subject.
And by reigniting the UFO narrative, they are more likely to receive reports and data from the public who may be looking for Aliens.
Interestingly, if this were true, it might imply that there is some pretty funky military tech out there, not owned by the US, that might have some interesting capabilities.
Things drones can't do: go fast enough to cross the sky in a blink, stop on a dime or turn sharp corners at jet speeds, travel at jet speeds at all - without an obvious and loud model jet engine, create slabs of light or opaque surfaces, block the stars behind them like a solid object, be eerily silent.
Eh, if you have an LED screen in the sky, you can create the appearance of a lot of things.