You're going way further with it than I would...
It doesn't have to be demonstrated, it is a fact accepted by both sides that WTC 7 was the first tall building in history to collapse from fire.
What is scientifically more appropriate (i.e. sufficiently precise) is the question '
Have structurally similar (in the critical respects mentioned in NIST FAQ answer No. 15) buildings ever collapsed from fire?'. The answer appears to be a resounding 'no' and therefore we simply have no precedents. One Meridian seemed to have been close to a collapse though, but the fires lasted much longer and it didn't have the same structural failures as WTC 7.
I wouldn't say the only viable hypothesis, but it would have been the exceedingly most likely hypothesis on the day after 9/11. It's just a completely mundane observation that if a tall building suddenly falls straight down, it probably did so for the same reason that every other tall building that has ever collapsed straight down did so, which would be controlled demolition.
Without going into the sloppiness and unscientific character of your reasoning (with all due respect), I basically got right what you're
trying to argue.
You could also state that if a building falls in a way that very closely resembles a controlled demolition, then it probably was a controlled demolition.
You could, but in so doing you'd be too simplistic and sloppy (read: unscientific) in your reasoning while ignoring all the other observables involved in a controlled demolition.
An explanation based on fire will require you come up with a brand new, never observed before mechanism, which NIST attempted to do.
NIST "attempted to come up" with no new mechanism. The NIST merely reported an investigation into and the consequent discovery of structural failures in WTC 7 that lead to the collapse from a fire which simply
were not present in the other cases you'd like to consider as historical precedents. Hence, the historical precedent argument falls flat on its face. Also the historical precedents of 'similar fires' on other buildings of similar size (which were cases in New York reviewed by the NIST team since New York is their jurisdiction and shares the same regulatory framework) are not that many to even statistically consider a pattern
even if they'd had fundamentally similar structural failures as WTC 7 (which they didn't).
You're also required to believe that a collapse resulting from randomly distributed fires looked like a picture-perfect controlled demolition, by pure chance.
If a critical column failure causes an entire floor to collapse, to a layman's eye the cascading collapse may look very similar to a controlled demolition indeed. Yes, science can sometimes be counterintuitive to us simpletons. However, it didn't look that similar to a controlled explosion
if you look and compare more carefully (which would be the more scientific/professional approach). Not to mention the other observables of a controlled demolition entirely missing.
Finally, since you wrote it's "entirely possible that WTC 7 was demolished while the Twins collapsed from impact and fire", then in that case this whole discussion doesn't belong into this thread.
I've said this to you before on another thread but it seems worthwhile repeating it. It's always possible that a rubber duck is in fact an extraterrestrial in disguise. But as long as the evidence for the more extraordinary claim is lacking, regarding a rubber duck a rubber duck remains the far more reasonable conclusion.
To heavily lean on a conspiratorial explanation despite poor evidence bespeaks, imo, of (1) a naive over-estimation of the intelligence and capability of powerful governments (the longer you've served one at a high level, the less naive you are about their omnipotence) and their sponsors and (2) a tendency to expect the worst of people in power (cliches like 'power corrupts, absolute power corrupts absolutely' taken as a hard and fast rule). Both 1 and 2 can be fuelled by popular fictional literature/movies as well as political forces wanting you to think that way.
But as we have been discussing I'm beginning to see two more reasons: (3) An unwitting hubris in a modern layperson and internet warrior leading him to think his untrained, sloppy reasoning and so-called scientific exploration is enough to contest career professionals who have immersed themselves in a given field
before giving these professionals the basic respect of properly immersing into their argument first. (4) A narcissistic need to feel special and non-mainstream.