[kaelinl]

Yes, my understanding (as purely a bystander) is that even the most aggressive fires in the past have allowed time for a mayday. See for example UPS flight 6, with a huge uncontrolled lithium battery fire: https://en.m.wikipedia.org/wiki/UPS_Airlines_Flight_6

In general, onboard fires are one of the most dangerous scenarios in-flight, as I understand it. Crews are trained extensively for it.

I think this is, in part, what the analysis in the article concludes — even a fire would have to cause a very specific, never-before-seen combination of failures to lead to the outcomes observed from the outside.