That doesn't at all address, in a scientific way, what happened to the steel vertical members of the core when the building collapsed. According to beardedbruce's report, the floors separated from the core. The weight of the roof and whatever other things were marginally connected to the core couldn't possibly account for the core's free fall speed as it came down. It would have been able to provide enough resistance to at least take a long time to come down, and very probably could have supported the weight of the roof (that part of the roof that was over it) enough for most of it to remain standing.

Prove me wrong.