Wag the dog

[Spectre X]

The thing is, Geggy, that the central columns collapsed. The planes pretty much cut them in half with the impact and the fire. They would have been able to stay up for a while, but eventually the inside would start to seriously collapse. The inside. Not the outside. The weight inside would start to pile up as floors colapsed onto each other, until the central columns would give away completely and just snap.