IIRC someone once did some math on the 9/11 aftermath. Many, many people worked on rescuing people, clearing the ruins and such, and most likely would have uncovered evidence of a conspiracy, were there any. Now, if the government bribed those people to keep quiet with say, $100 000 each, it would have caused a huge hole in the budget, noticeable to anyone keeping track of it. Similarly, making all the people disappear even after they've been seen on TV doing their work would be suspicious, the inflated bodycount doubly so.
Aliens: thousands of people watch the sky the whole time, and would notice any anomaly. 'Stealth systems' would be a plausible explanation, but stealth in space is so ridiculously inefficient (and it makes you effectively blind), it wouldn't make sense for the aliens to use it just to steal cattle or whatever it is they would want.
Illuminati etc.: Practically unheard of before Dan Brown wrote on them, and we know how his stories are '99% true'. In this modern world, it would be next to impossible to keep a huge project such as this secret, knowing how many people it would need to keep quiet, and some wouldn't anyway in order to become famous instead of rich.
Conspiracy theories just don't have a sense of scale.
One more thought about 'punk types: what would one call a 'punk genre based on the period from the mid-60s (after atompunk) through the mid-80s (before cyberpunk)? Transistorpunk? For a less technologically-based name, rockpunk?
Bit late on this, but...rocketpunk.