You've not mentioned the role of the UFO-believing public.
That's why you miss hypotheses like: the public, thrown in doubt by the rise of social media and the decline of traditional media, is now more credulous than ever, and among the various conspiracy theories that have come to the fore (who could've predicted anti-vaxx would rise that far), UFOlogy has gained such a large following that they now have enough political clout to affect the DoD. It's all birds, balloons, and other prosaic explanations, but nobody believes the DoD when they say that.
This isn't a new phenomenon, when I read the CIA documentation we discussed earlier on this subforum, I had a strong sense of deja vu. This was how project blue book and the Condon committee got instituted. Maybe it's just time for another fruitless round on the same carousel.
Having recently watched "The Phenomenon" an overwhelming impression that I took away was that the Roswell incident was indeed a military operation gone awry and that the original denial of official involvement was useful at the time in keeping 'the secret', by which time the media had spotted an opportunity to sensationalise the incident, which in turn fuelled the appetite of the public. Look up "The great moon hoax of 1835" for an early example of media fuelled public frenzy.
The many attempts thereafter by the authorities to close down investigations was then construed as further proof that there was, indeed, a cover up of some kind, with later investigations funded and initiated by monied individuals, the main culprits being Rockerfeller, and more recently, Bigelow, both of which had/have a vested interest due to having companies based around the aerospace industry.
Could this be a case where a little white lie, in order to conceal covert operations has just spiralled out of control?
Materials not of this world found at the crash sites are plausible, for instance, if i were to have stumbled across a heat resistant tile that fell off of an early shuttle test, I probably wouldn't have recognised it as from this earth.
Similarly witnessing a prototype stealth fighter flying night runs out of area 51 in the mid 80's, or the Harrier [jump jet] as far back as 1969, they would appear to defy all known laws of aerodynamics, and imo still do, particularly with maneuvers such as the cobra roll in modern day machines.
The hearings were predictable in their ambiguity, and under oath, anybody could appear to be telling the truth when the questions are preceded with "and do you beleive..."