A reasonable argument seems to account for the cargo capacity per unit of pollutive emission. I don't have the numbers but my wishful-thinking-o-metre is high.

A reasonable argument seems to account for the cargo capacity per unit of pollutive emission. I don't have the numbers but my wishful-thinking-o-metre is high. And since that metric was off the radars in 1930s, that is definitively new compared to the last era of airships.