All the conspiracy theories that are pulled out of people's asses, I still would find it hard that a country would do this to themselves.
That is why all these theories will remain just that; a bunch of unproven hypothesis. Despite the past few years the US is still a remarkably free society. Yes conservative propoghanda and view points have become dominant but this is more because of Liberal complacency and failing to stand up for themselves more in the past decades.
If those people who propose all these alternate theories really wanted to prove them there is no reason they couldn't. There exists a free press, a right to freedom of speech and to believe whatever one wants to believe. There are universities and other academic institutions where scientific research could be conducted to prove (or disprove) the theories regarding the physics of the collapse. There are plenty of crazy, eccentric rich people who would probably help with funding. There are plenty of media outlets where the message could be spread (and has) and could also assist in valueable journalistic research.
Yet there seems to very little interest in actually conducting the valueable scientific research which could easily prove (or disprove) many of these theories. Instead most of the effort seems to focused on creating lots of theories and ideas and scenarios as too what happened, broadcasting them in media, and then accussing the government of hiding information when their stories (which is largely all they are at this point) are not taken seriously.
The truth is not black and white. It is not just one persons, or one countries fault. It is a complicated event that covers decades of domestic and international politics, religous ideologies, arrogance, nationalism, empire building, and likely hundreds of other factors. No one book, movie, person or discipline can summarize it up in a nice neat package that is easily understadable.
And thats exactly why conspiracies will continue to live on. They are simple, easy and require little effort. They are wild stories straight out of an action movie that provide answers, salvation and adventure. Perfect for sequels. And they give you enough time to be home and in bed for the 11:00 news.