LOL 

>"...why isn't there a world wide programme to upgrade the main structural support fireproofing in order to avoid the potential threat of collapse due to office fires?"

Because the people that would have to fund it know better.  

People with immense holdings of capital tend to be fairly practically minded, and it is impossible that office fires caused these building collapses.

Thermite/thermate.  

Not to mention that if you crash aluminum into steel it is the aluminum that is deformed.  The Pentagon was not pierced by a plane, but a shaped charge.