They were basically the Mongols of North America. It was just their bad luck to have their acquisition of horses predate the presence of industrial firearms by only a short time.

And, that same coincidence was the very good luck of everybody who wasn’t Comanche.

Unless the homicide or infanticide rate was really high amongst themselves, in which case you’d suppose they’d fail at keeping outsiders from taking over their land.

Comanche and other war-like tribes were big-time slavers, too. They made slave raids into Mexico on a continuous basis and also bought other American Indians from tribes such as the Navajo. In that context the battles fought by Kit Carson can be seen from 150 years ago as an extension of the American Civil War.

This is not entirely stupid as the northern plains are being voluntarily depopulated, and the Indians are agitating for more free-roaming buffalo. Of course, such an eventuality would raise Holy Hell with highway and railway traffic, but maybe the roads and railways would be torn up as part of the plan.