Was It A Conspiracy?
There is a video of a simulation of the WTC collapse on YouTube. It shows how a heavy airplane, moving at high speed, slices through the columns supporting the building. It also shows the fuel catching fire and unleashing a firestorm against the remaining steel supports.
Was it a conspiracy?
Did the builders ask Boeing about the weight, speed and fuel load of airplanes flying 40 to 50 years into future? Apparently they did not.
Did the builders enclose all the steel columns and floor supports in fire proof concrete? Clearly not.
The reason is obvious. If the builders had asked all the right questions and designed the buildings with safety the primary consideration, there would have been a greatly reduced amount of rentable floor space at the higher levels.
Does that constitute a conspiracy? Perhaps not, but it does seem like negligence or excessive eagerness to maximize profits on part of the building owners and willingness on the part of the engineers to cut corners.