NB, as shown by the Kobe ,Japan earthquake both concrete and steel buildings had the same failure rate, so one material was no more inherently weak, when both materials design account for the same forces. Detailed right, both materials can compensate for lost columns.
As I understand it both the concrete Murrah building and the steel WTC7 suffered an initial column failure (one by explosion, one by heat) under transfer beams/girders . So the WTC7 loss of one steel column did not prevent global collapse. Perhaps the lesson here is that transfer beams should not be used in buildings subject to potentially abnormal loads, not what material to use. Embassies choose poured-in-place concrete for blast resistance and thereby survival from collapse.
The main point I want to make is that the steel Towers were not of typical design and were weak to fire and non-redundant in its vulnerable long span non-columned lightweight floor truss design.
(Not that I would have done anything differently.)
For steel buildings either the fire goes out before the building collapses or the building collapses before the fire goes out.
The plane damage and the fires fully explain the gravity-only collapse of the Towers.
