A motive is the key.

Could it be that if we find the motive for these actions , we might be able to figure out who the perpetrators actually were?Why did they choose the only buildings in the U.S. that were insured against terrorist attacks ? You could not and still can't insure any structure against terrorism but the new owners of those buildings collected billions of dollars after the attacks.
One would have to believe an attack of this magnitude would bring about retribution never before seen. Would a terrorist group risk the wrath that would surely follow such an attack? The planning and execution of such a plan would require some intelligence so why would they not be smart enough to figure out they could damage the American way of life much more by attacking the infrastructure needed to maintain a city like New York. The city could have been brought to a standstill by disrupting the subway system or the electrical supply network that could have been accomplished with much less effort and less retaliation.
You would have to go back ten months to find the most important motive for these attacks. The election of 2000 which was actually won by Gore but stolen by Bush was about to be exposed as a complete fraud perpetrated by Bush/Cheney . The election commission report would have led to the impeachment of that admistration and exposed the U.S. as nothing more than a corrupt country controlled by a bunch of crooks bought and paid for by lobbyists in D.C. The report was never seen and acted on because the U.S. was under siege and it was not the time to bring down the government. Other less important goals were accomplished at the same time with the destruction of WTC 7 and no one can explain why that building imploded without any planes crashing into it. How they did it next time.