I am not an engineer, just a dumb architect... and it seemed intuitive to me that if the entire EPH came down... and it was a large section of the East side of the roof... more than a single column would have had to fail. Of course NIST's explanation is that the failure progressed FROM the col 79 failure despite their animation not looking much like the actual collapse. And as it turned out... something I was unaware of at the time I had the intuition... there were several massive transfer trusses under the EPH and connected the west side of the core and especially the north column line... and the failure of the north column line of the core coincides with the westward progression of the collapse observed (WPH). Of course there would be no "office contents" fire in the transfer region and so the fuel would have to be diesel... and they dismissed diesel for some reason... although I am sure it burns hotter than paper. Go figure.