Do you know that to be the actual weight of the above floors? I don't, but even at that, going back to the can, a 200 pound man (me, just did this for proof) is supported by the can easily. That is approximately 6,142 times the weight of the can at 0.521 oz.. Using these numbers it would seem that the remaining undamaged floors would total 81.41 tons, and thats only if the lower portion equaled the strength of the can providing the 500k ton number is correct. Seems like an aluminum can would be an excellent building material.
Speaking of seismic, IIRC the collapse showed readings at 2.3 and a 2.1 respectively on the Richter Scale of the actual falling of the towers. To me that rules out any seismic arguement especially for WTC7 as that fell hours later.
Wind, no significant change there either, it was a clear calm summer day IIRC.
Lets just agree to disagree on the how they fell and agree that we will never know the whole truth.
It is one of the essential features of such incompetence that the person so afflicted is incapable of knowing that he is incompetent. To have such knowledge would already be to remedy a good portion of the offense.