Wow! Fantastic summary! Great links. As a huge, current X-Files fan I love the concept that conspiracies used to be kooky until they got so serious. I think it might be because conspiracies used to be about curiosity - discovering the truth of the world and the way it works, a response to the oppressive hood of religious dogma. It was about science, the balance between Mulder's out-there ideas and Scully's precision.
But then science won. We pulled aside the curtain, as a culture, and we learned there was no one behind it, no Wizard of Oz, no God, no competent President we owed loyalty, no great influencer pulling our strings.
I think that divided us into those who stopped looking and those who insisted there was someone else in control, now a nefarious force, equal to the acrimony we felt for the lies we once believed. This was necessary, because without someone at the top it meant that all the bad things happening were our fault, our failings. Some people just can't face that fact.