I think in the past, we also used to have a "tyranny of the horse" equation. If you needed a horse to pull a wagon some distance over terrain unsuitable for gr

I think in the past, we also used to have a "tyranny of the horse" equation. If you needed a horse to pull a wagon some distance over terrain unsuitable for grazing, you needed to carry a significant amount of fodder for the horse. The longer the distance, the more fodder you needed and thus the more load for the horse. If you were so heavy, you needed 2 horses, then you needed even more fodder. This was a huge limit to ground transportation in the past.