Notice the successes that would have happened IF the fire could have been put out (in 2-4 hours, maybe in 4-6 hours) .... Nobody knowss how the building might stand.
First. The 4,000 - 8,000 people alive in the floors ABOVE the impact area would have been saved by the first firefighters to get through the stairs.
Second. IF the fire could have been out - and it certainly MIGHT have been under different circumstances - the weakened structural steel - WHICH DID withstand the impact of the collision for hours - might have been strong enough to give enough time to evacuate the whole building.
Third. IF the fire had been put out - in one or both buildings - then the damages MIGHT have been limited to the immediate fire and explosion, since the buildign might not have fallen at all. Not 10,000 dead and 3 billion dollars of losses.
Your loss is very real - but the firefighters WERE NEEDED to TRY to reach/protect/evacuate those thousands of the higher-level occupants - who were still alive until the building collapsed.
Also, until the collapse itself began - there is NO WAY to predict how long the building would stand....minutes more, hours, or "forever" -
Nobody at street level could predict how long, if ever, the building may stay up. You cannot tell from the ground, or even in the fire itself, how strong any given steel member is without rigorous lab-condition analysis. And even if you know how strong any single member is, you can't tell without hours of elablorate computer simulation, what's the result of one or more members failing. Since the damage was widespread, over several floors, and was in the midst of flames ..... you can't take the time to analyze - you MUST PROTECT IMMEDIATELY those threatened.
(And of course, removing steel pieces from the building is impossible during the fire. And would weaken the building itself. Even surveying the building would delay other rescuers from going up to try to make a passageway down for those trapped.)
If the building did not immediately fail - which it did not - then the those trapped and burning to death up became priority.