That's ridiculous. It wasn't too expensive, it was IMPOSSIBLE. They would have had to take the 67 floors down and start over. You can't suddenly add tons of concrete to the top of the structure, the weight is one of the main factors in the design of any building.
Encasing the beams in concrete would also have affected the stability of the building in terms of the main stress the designers were planning for--the wind. The towers were designed to sway, and anyone who's visited them knows they definitely did. That's so the very tall buildings won't topple over in a hurricane. Make the structure more rigid and you've put it in danger. Again, the building would have had to be completely redesigned from scratch. It would have to be built differently to accomodate the differences in weight and flexibility
Asbestos being banned was out of the Port Authority's control. The fireproofing eventually used was up to code, and you have provided no evidence that its use was a cost-cutting measure, or that it saved them any money at all.
The question was not the cost of the alternative fireproofing method, but rather the cost of the above choices 1 or 2.
I have just shown you that there was no "Choice 1", unless you really think there was a choice to tear down perfectly good buildings at that point and start all over again. In other words, to waste the millions of dollars that had already been spent.
Your claim was that the towers were cheaply built. Stop trying to dance away from what you said, it won't erase your first post from this thread. In fact I'll post it again:
WTC collapsed because the towers were built "on the cheap".
When the construction crews were prohibited from spraying asbestos to insulate the steel columns (see: New York Times, April 28, 1970, p. 83), the towers should have been built to a shorter height, around 70 stories.
Do I have to point out that the "cheapest" solution of all would have been to stop building right where they were when asbestos was banned? Think of the money they could have saved. Yet you said the towers fell because "they were built on the cheap", even though you provided no proof at all to back that up.
You have a strange malfunction in your brain, Tuco.
So the choices were stop building at the 67th floor level or "invent" a new fireproofing technique.