I don't follow your disagreement exactly. Are you saying that people in the past got strong from body weight-only exercises?
I have been thinking about some fairly strong people that I know that have never lifted barbells. I come from a farming background. I'm pretty sure they didn't get strong from body weight exercises. I think about my friend Tim W, who was maybe about 350 and not fat. He would pick up 2 80 pound bails of hay in each hand. Pause then throw them to me at the top of a high hay wagon. Or him picking up heavy farm implements etc. I never saw him deadlift, but remember the time my 300 pound motorcycle the wheel would not turn. He picked it up and carried it half way across the field to the barn.