I've heard traders at banks literally yell something like "Just fire the entire useless IT department and just let me use my Excel!"
Given a complete set of requirements and a working prototype, will the IT department ever finish writing software that meets those requirements?
Okay, that was sarcastic, but illustrates a real problem, which is that doing it in Excel is making something, whereas getting IT involved is managing something -- a category error. The problems of managing software development are unchanged, half a century after The Mythical Man Month.
Asking for software is like a gestapo interrogation - your always not right and in the end all motives are questioned.
We currently migrate everything to the cloud, which breaks many Excels that so far got their inputs from on-prem services or the file system. What could previously be deployed without second thought now requires extensive, decentralized cloud knowledge in each team. Power is taken from the lay business user. What took seconds in VBA now requires a feature request to a dev team.. it's insane.
I'm in HFT so we have software engineers available to our portfolio managers. Everything is in code.
Live strategies are deployed via a script that ultimately ssh to a machine, plops a set of artifacts in from storage, and then runs. But everything needs to restart together.