Sprinklers may have helped, because while they would have spread the burning jet fuel, they also would have spread OUT the burning jet fuel, and whatever ignited because of it would have burned cooler. Also, the water might have cooled down the beams enough to keep them from buckling.
On the other hand, with an airplane just having run right through your sprinkler riser system, it’s not going to be easy to get water above the fire. Just one of those things nobody thought about before — what to do if someone drives a plane through your building.
The towers were designed to absorb the impact of the largest commercial airliner of the day, the Boeing 707.