The idea goes ,via the Samovar, all the way back to about 3600 years ago with vessels made out of pottery.
The Thermette was , in my mind, an utilitarian version of the otherwise ornamental Samovar.
One point that some raised with the Backcountry boiler is that because of the flat opening they dribble when pouring. (that is the kettle dribbles, not the owner overcome by the excitment)
Oddly I don't dribble. I might be doing something wrong...