With the impact of the airplane to remove insulation, and multiple floors on fire, there are plenty of problems for the steel.Nobody is saying it can't eventually if heated long enough with a hot enough fire.
It depends on the size and heat capacity of the steel, the size and proximity of the fire, and whether the steel has a sink to transfer some of the heat to.
Have you considered the limitation's of NIST, that steel considered as evidence in the investigation had to be identifiable by it's chalk marks?NIST found no evidence of the steel they received from the towers experiencing high temperatures. This would have been due to the size of the steel, the size of the fires, and the fact that the steel had large sinks to transfer heat to.
