I recently attended a briefing on the entire forensic engineering study of the WTC Attack given by the head of the commissioned study team.
The jet fuel itself wasn't so much a fuel source causing the fire to burn hotter as it was an ignition method that caused the fire to be non-typical.
A third of the fuel burned outside the structures, in fire balls and explosion, a third ran down inside creating incidental fires, and a third spread through out the floors involed with impact like charcoal lighter fluid.
Thus, that last third, caused the entire contents of those floors to begin burning at the same time. Like charcoal lighter, it burned off in twenty minutes or less. The subsiquent fire was non-typical because it wasn't progressive, proceeding form an ignition point. Instead, great temperatures above typical developed because of entire floor burn progression was happening at the same time.
The structuures preformed beyond their design and were designed ahead of their time. Different uses of fire-proofing were the only things that would have prolonged the callapse, but only by minutes. Hardened core systems would have made a difference to victims above the fire, but that is the issue in any highrise.