Game numbers may have been higher in some parts of the North American continent, but not everywhere was necessarily easier.
A book on Kit Carson stated that he needed to arbitrate an agreement between the natives around the Purgatorie River, SE Colorado and a ranch. Seems that a few rifleman killing deer to feed the new ranch operation disrupted the hunting enough to cause a stir.
And I read that Indians in the Idaho Rockies would get close to younger deer, does and a small ones, hanging out, not be threating, so when the bigger deer came in, they stood a better chance of a harvest. Maybe that was in Primitive Archer....
The Yavapi Band that hunted the Eagletail Mtns, sheep, and lived near the Colorado River in SW Arizona would get skins, other materials from other bands and create functional art, as their own area lacked some resources.