Yes, their land use would have never supported that population. In fact, many of the Plains Indians were descendants of eastern tribes that were pushed westward; before Europeans arrived the plains weren’t teeming with Indians. The fact that they didn’t have horses until the European arrival puts to rest any idea that the buffalo hunting horsemen’s way of life was “thousands of years” old.
The theft of land is hard to excuse, though the natives themselves played a large role in the French & Indian Wars for control of upper North America; the French in particular would have been unable to fight without them (as their pool of settlers was much smaller).
Even in early skirmishes with settlers (pre-independence), the tribes themselves weren’t very large.
The Indians were not Jews lined up for slaughter. Many of the tribes were warrior by nature. I've visited many colonial houses in Massachusetts with their “safe houses.”
“Theft of land’’? It always surprises me that a people who proudly proclaimed to have no concept of ownership, ‘’owning’’ the land, water and sky, as it were, suddenly start acting as if they’ve been the victims of massive fraud and the land and water they never owned is/was ‘’theirs’’. What a crock.