Your article makes me wonder how closely Mr. Galbraith read primary sources like the trading post journals. I took a class in university on the fur trade centering around Fort Edmonton in what's now Alberta in Canada, and it was clear how Indigenous nations could be hard bargainers. One entry had Fort Edmonton's chief factor pleading with his superiors to give him better merchandise because he was losing business to the Northwest Company (the Hudson Bay Company's rival in the late 18th and early 19th centuries). He said the local Cree and Blackfoot customers didn't want the tobacco the HBC was offering and he couldn't blame them, since it stunk like rotten cabbage when it was lit. I got all that from just one class.

The things you describe in this article were common all over North America. From what I recall, the James Bay Cree were very touchy about any other First Nations trading directly with the HBC, and were ready to violently protect their 'middleman' status. And even when Britain was the only major imperial power that First Nations could trade for, competition could still come up when some independent Scottish and French Canadian traders formed the Northwest Company as a rival to Hudson's Bay.