Yeah, and we had been doing that sort of thing in New Zealand and other places around the world for over 50 years.
Unfortunately a lot of the rescue operators don't talk to the utility operators to see if they can learn anything. Yes it could have saved lives in 9/11, however the response time needed may have limited the number saved, and unfortunately we will never know if any could have been saved.
Also the commonsense thing to do in a tower fire is to descend, so how many people would have headed to the roof, and most roof access is locked...