The structure is the key to how and where is collapsed in my opinion. I believe the massive trusses were site built and bolted together. Those structures spanned the substation because the axial load path could not pass thru Con Ed. This is the more likely location of the failures which brought the building down. FEMA and the building's engineer Cantor thought this was the place to look. My hunch is that "politics" played a role in not scrutinizing the structure down there.