One more question for you. Does the fact of more accelerant mean faster consumption of the available tinder?
All of the fuels available will burn at the same rate, releasing the same amount of total energy.
There is an upward limit to how much heat jet fuel will produce. The same applies to any of the Class A fuels present in the towers.
In an ordinary office fire, the papers and furnishings would have started burning from one or two locations and then spread throughout the building, producing a lot of heat locally for a limited time. Normally, much of the heat would have been dissipated by convection through the air or by radiation as infra-red light to the outside, or by conduction through the steel itself. Steel is a reasonably good heat sink up to a point. A good illustration of this is an old fashioned branding iron heated in a wood-fuel camp fire. The handle will get a bit hot, but leather gloves will shield a human hand from it, while the glowing red end of it will sear a mark into the tough skin of a cow.
What the use of an accelerant (in this case, kerosene) did was to initiate the fire from multiple and wide-spread points so that they quickly merged into a very few intense fires. At this point the heat energy from combustion of both the remaining Class B and the newly-ignited Class A fuels will be released throughout the area, probably faster than it can be lost to convection, radiation or conduction.
This, of course, will mean that any exposed steel will be heated more rapidly to the point of failure.
The sheet rock and spray on fire resistant material would normally shield the steel from most of this heat, but only for about two hours, the expected time required for fire fighters and/or installed sprinklers to extinguish the flames.
However, the impact of the aircraft removed a great deal of the SFRM and the sheet rock at the same time that the fires started and broke water standpipes so that there was no water available to fight the fires.
Thus, the principle effect of the accelerant, in this case, was to do in an hour or so the same amount of damage that one could have expected over the course of five to ten hours.
Steel will, eventually, fail in an intense fire.
This one, because it went from zero to balls-to-the-walls hot within minutes, was very intense.
The steel failed.
This is Fire Science 101 stuff.