If it all exists, I am pretty sure all this technology has considerable value for the military and as such, there will be immense resistance to acknowledge anything.
There's a lot of "somethings" that could be the case without it having anything to do with actual aliens existing. The two broad categories would be that it's an intentional cover story for something meant to be secret, either legitimate research or some kind of corruption -- or it's sincere crackpot research in the government, of which there are plenty of examples, from paranormal research to ordinary pseudoscience.
I truly believe that all UFO sightings have been terrestrial technology tests or atmospheric events. If a flying saucer had been found that was capable of interstellar travel we wouldn't have dinky two person ones sitting in a museum. They'd be the basis of mining tech that would empower the finding nation.
This is basically the only available truth (if you add in people hallucinating/misremembering/etc). The problem is you can never “prove” this to someone who wants to believe otherwise.
Let’s say the government legitimately did lay bare all of its UFO related classified documents and it explained some portion of events with known military secrets. There would still be a huge contingent claiming they were holding back something. And you could never prove them wrong. There is always a deeper secret to a conspiracy theorist.
Ask yourself: why and how does only an extremely limited number of people in the US government consistently have access to what feels like a steady stream of alien crafts going back to the 1930s? Why has no one else recovered these? Why doesn’t congress know? Why didn’t Trump know (picking on him because we all know he’s not great with keeping secrets)? Why would aliens go out of their way to stay hidden? Why would they travel hundreds of light years (or more) to earth, only to immediately, and consistently, crash at a speed that leaves largely recoverable parts? I recommend researching what the aftermath of plane intercepting the ground at a comparably paltry 500mph looks like for reference.
Compare this to the alternative explanations, all of which are completely plausible. Nothing about it being aliens makes any goddamn sense. The only thing that makes sense is it’s bipartisan, because no politician in their right mind would be against this, if only because that would make you look suspicious/untrustworthy.
With our current level of technology we have not lost a major airframe in the US since 2001. Yet these beings advanced enough to fly across interstellar space get to earth and suddenly can't keep their ships in the air?
I also encourage those who are very skeptical to think about how we as human would likely try to explore other star systems, in fact we already have started such projects. Our first step is to send a craft that with subliminal speed takes 100s of years, but even us we think about sending a craft with smaller probes inside it.
My point is those probes inside the transport craft, we would likely have a pretty high loss tolerance, so is it really that surprising they might crash sometimes?
Look, I'm beyond skeptical of the claims, but it's not because the spacecraft shouldn't crash. The most likely time to lose an airframe is on takeoff or landing, not in between, so why wouldn't the aliens have problems once they reach their destination?
Because they've consistently failed at providing proof, every single one of them. I guess aliens have galactic-level OpSec, defeating every whistleblower so far.
The town square remains empty!