Semi-related, I read an interesting piece about the possible last survivor of the 7th Cavalry.

https://en.wikipedia.org/wiki/Frank_Finkel

The Beast of War is the subject of the recent documentary "Only the Dead" on HBO.

This is a beautifully written article.

This article told me absolute zero about counter insurgency or about how lessons from the great plains might apply today.

What led you to expect any of that when you clicked on the link?

The first paragraph of the article heavily implied that a comparison would be made between the insurgency and counter-insurgency tactics of mid 1800s American great plains and modern day Iraq and Afghanistan.

IMO that would probably make a more interesting article. While obviously IS and the Native Americans are ideological worlds apart, both groups ran/run an insurgency against the technologically superior US army. It is worth noting which tactics work and which do not.