What I do know is:
a) it's idiotic to demand hard proof of such things, instead of using the best of what information is available to deduce if it's possible or not
b) As Gore Vidal put it: "Americans have been trained by media to go into Pavlovian giggles at the mention of 'conspiracy,' because for an American to believe in a conspiracy he must also believe in flying saucers or, craziest of all, that more than one person was involved in the JFK murder."
c) After something comes to light, be it Enron, the financial deregulated party going on pre-2008, the revelations about mass surveillance of American citizens, etc, idiots -- who previously was all jokes about "that's absurd" -- come out saying "of course, we knew all that all along"...