This is true, but it is reasonable to expect the computer modelling effort to at least attempt to model the part of the event that is of most interest.
The greatest interest would be how the internal collapse progressed thus resulting in global collapse. THAT is what the FEA modeled. So wheres the beef?
In this respect NIST falls at the first hurdle, as it did not remotely attempt to model the part of the collapse where the building dropped with free-fall acceleration as a single unit.
No, why would the FINAL few seconds of collapse be the most significant? As JO noted above, your characterization is also grossly in error. That's like saying that in a car accident one needs to understand the dynamics of the car being torn apart in order to understand how the accident occurred.
Instead it hypothesised an "internal" collapse and used a computer model to support this hypothesis, but stopped the model long before the "facade" could be demonstrated to fall in a manner even approximating what was seen. So NIST actually proved nothing, at vast public expense
Again, no. An internal collapse was patently evident with the collapse inward of the EPH, then the more western rooftop structures, and the north face "kink".
NIST then analyzed the effect of how the failure of various columns would have on the EPH. It was determined that the best fit to observation of the infalling of the EPH was failure of column 79. The collapse FEA then considered its starting point to be a failure of column 79.
The FEA demonstrated an internal collapse prior to global collapse in a fashion that did in fact resemble what was observed. You seem to believe that there was no FEA performed at all and that the animated internal collapse was simply manufactured.
To expect that with the additive effect of uncertainties, that the FEA would be or could be completely accurate as to gross building response near the end of the collapse progression, is ridiculous.
Taking it further, NIST investigated how column 79 could fail. The ONLY proximate causes in evidence were the impact damage from the collapse of WTC2 and more to the point, WTC1; and the unfought fires in WTC7 itself.
Impact damage to the south side did not include enough evidence to suggest that it was a primary factor in the much later progressive collapse. There was scant evidence that impact damage had reached the building core, basically only that one elevator car had been ejected from its shaft.
So the other factor, fire damage was considered. To that end one looks for fires that occur in the vicinity of column 79. The most prominent being that on floor 11,12,13. A fire Sim program was used to determine heat in that area and it was determined that direct heating of column 79 was insufficient,
in itself, to cause the column to be close to failure. However, floor failure would remove lateral support for the column. A mechanism by which this could occur was found, movement of the girder between col 79 and 44.
In addition, the investigation found that col 79 moved a short distance to the east due to other members expanding.
So, col 79 is hot but not hot enough to directly cause it to fail AND it likely bowed to the east at the fire level due to expansion of horizontal structural members, AND the girder between col 79 / 44 was also being pushed in the opposite direction. There may well have been several other smaller effects , such as the effect of the south side column damages, that contributed to the girder coming off its seat.
Jeffrey Orling has a different scenario which definitely also could match the EPH in falling. That is the failure of TT1 and the consequent failure of columns attached to it. My sole beef with this is that there is no demonstrable proximate cause of a TT1 failure, and that is why NIST did not consider it "most probable", which is how all of their scenarios are characterized.
Now you know.