Often researchers and tenured staff held on to such artifacts but eventually retired or died.
Their offices were emptied out by random staff who had no clue of the significance of their possessions and thrown out of left in a collection bin in the hallway.
I've got a few gems I rescued from such situations, so I wouldn't be surprised if this was what happened, even if not, it's worth knowing that this happens :(
Until the era of thumb drives came along...
I'd wager it has more to do with the... significant overlap between rocket guidance and long range missile guidance. Nothing to stir up a good panic like the thought of the latter ending up in North Korea's hands - how much good it'd actually do NK being entirely besides the point.
After Apollo 11, President Nixon presented moon rock samples as gifts to various countries and states. Over 180 of them are now missing, and the FBI investigates people who are allegedly selling them (hint: they're usually fakes)
The whole 6 part documentary series are worth watching for anyone remotely interested in space, but here's a small sample of the quality of the moon landing video footage: https://kristofferR.com/files/moonlanding_footage_HD.mkv
Let's just focus on a space station and travelling to the red planet we know little about. What footprints on the moon?
I've never observed this to be the case, and I collected conspiracy theories for a good few years. The people who credit them tend in my experience to be a rather close-mouthed lot, not least because they're accustomed to ridicule, and probably the very last word I'd choose to describe them would be 'hip'. I'm curious what you've seen that leads you to consider otherwise.
OTOH, back in those days, maybe there was more of a sense of pushing things forward, and less nostalgia, and maybe that was a good thing. I can't decide if I like having every speck of computer history catalogued and put in a museum. For one thing, I fear that 50 years from now, people will cling to the stories of the creators of Android or iOS or Pokemon Go, and somehow that old Nokia flip phone I have in my junk box will be a museum piece.
Nostalgia. Can't live with it, can't live without it.