I don't disagree with your post, but one thing I want to mention is the origin of the term "Incident Commander"--it doesn't exist to be cool, but rather derives from how FEMA handles disasters. I suspect its usage in IT became a thing because it was already used in real-life, and it made more sense than creating a new term.

If you have two hours, you can take the training that describes the nomenclature behind the Incident Command System, and why it became a thing:

https://training.fema.gov/is/courseoverview.aspx?code=is-100...

This online training takes about 2 hours and is open to the general public. I took it on a Saturday afternoon some years ago and it gave me useful context to why certain things are standardized.