Okay, I disagree and here's why:
1) All of the contents of the building were required to meet standards approved for fire safety. The insulation around the steel is hardly the only step taken to avoid problems should there be a fire. There were (seldom mentioned) water systems, all contents, desks, computers, cheap fake plants, had to follow code (nothing that could burn too well was in the building). According to NYC
code, all wood must be pressure treated with fire retardant chemicals. The paint on the walls must be fire retardant. The floor, carpet, wood, cement, etc. must be fire retardant. When any of these did eventually burn, it would have been slow and cool. In addition to this, I cannot find anything inside the building that could have burned at more than a few hundred degrees. Computers would burn low and slow, mostly being melting plastic. Chairs would be much the same.
- Black smoke still = low O2 fire. Either you skipped that, or you agree. If you skipped it, I hope you'll indulge me. If you agree, then it works with what I wrote above to suggest that the temperature and severity of the fire after about 10-15 minutes would be small and inconsequential. How well do you think plastic burns in a low O2 environment?
- The building collapsed in under an hour. While I could easily understand that the building collapsed after maybe 8-10 hours of burning, the thing dropped is less than an hour and it fell at free fall speeds. This would suggest that the crash did damage to the entire structure instead of just the entry point and surrounding areas. Also, it gave at once, suggesting that the heat of the fire was able to weaken the remaining steel in a hour enough to cause it to lose it's strength.