When you consider the 9/11 commission, the NIST investigation, the FBI etc, there were countless people looking at all aspects of the attack...
For any of these far fetched theories to hold water you have to ignore all the contradictory evidence that points in another direction and that countless experts investigating it willfully ignored the points you raise.
As I've noted elsewhere in this message board, the U.S. government ultimately settled for an investigation that even its Republican leadership considered to be inadequate. To quote Peter Tatchell of the Guardian:
The chair and vice chair of the 9/11 Commission, respectively Thomas Kean and Lee Hamilton, assert in their book, Without Precedent, that they were "set up to fail" and were starved of funds to do a proper investigation. They also confirm that they were denied access to the truth and misled by senior officials in the Pentagon and the federal aviation authority; and that this obstruction and deception led them to contemplate slapping officials with criminal charges. - 9/11 - the big cover-up?