> You're really missing the point. The volume of cargo carried by sailing vessels in the old days was orders of magnitude lower.
At the end of commercial merchant sailing, the largest steel hulled merchant sailing vessels were about 1/10th the cargo capacity of a modern container ship, but actually pretty comparable in speed, which is limited more by the physics of displacement hulls in the water than the propulsion method.
Historically, sailing ships risked becalming, but that is no longer a risk, with improved weather routing and backup engines that allow them continue at full speed if the wind dies.
Considering that the cost of modern shipping is 50-60% fuel cost alone, and that in principle with modern tech sailing vessels won't require large crews, it is not clear to me that it can't be economically viable nowadays even at the scales already possible a century ago, nor that it would be impossible to develop tech to scale merchant sailing up to modern container ship sizes.
At the end of commercial merchant sailing, the largest steel hulled merchant sailing vessels were about 1/10th the cargo capacity of a modern container ship, but actually pretty comparable in speed, which is limited more by the physics of displacement hulls in the water than the propulsion method.
Historically, sailing ships risked becalming, but that is no longer a risk, with improved weather routing and backup engines that allow them continue at full speed if the wind dies.
Considering that the cost of modern shipping is 50-60% fuel cost alone, and that in principle with modern tech sailing vessels won't require large crews, it is not clear to me that it can't be economically viable nowadays even at the scales already possible a century ago, nor that it would be impossible to develop tech to scale merchant sailing up to modern container ship sizes.