one thing to also keep in mind is no matter the sophistication of models, there is always gonna be some person in front/middle/back office somewhere, running a critical process on excel for 3 years.
While they're stashed relatively deep in my memory banks (mostly for the purpose of forgetting), I do have dozens of experiences 'touching up' PDFs, reverse engineering or cloning things from PDFs of PowerPoint presentations, or otherwise using whatever digital hammer and chisel would get the job done. Screenshot > Paint > Fix > PDF, boom!
The real reason is because Excel is still by far the simplest, quickest way to get something done fast when the deadlines are always "yesterday!".
JPM/BAML/GS have fallen down due in large part to their choice of language in my view. A graph database written in a hurry in C++ then glued together with tens of millions of lines of hacked up python is not the way to build a bank wide platform in my book!
[EDITED to add: This is also the first link in the OP.]
I see this elsewhere too - solving business problems with software tools not with business tools.