That's an interesting thought and it deserves special attention. When the US was 'building the bomb' how many people who were there for the whole time knew what they were building or knew how to build one. Patriates are just as fanatical as any other fringe element.
Lets track the careers of each and see who got promoted or otherwise benefited monetarily and 'position-wise' since that event.
Why doesn't someone on the conspiracy side make an estimate of the people, assets, resources, companies etc that were needed to carry this out. I mean people directly involved with the WTC site. The planning, delivery and planting of explosives. Come on, it's science not just looking at grainy youtube videos made by Kakato.