Re: Why not a cargo version
"Because nothing - absolutely nothing - can beat ocean shipping for costs."
Cost is not the only factor. Often customers are willing to pay for speed of delivery, especially with JIT manufacturing.
Also not everywhere is next to a ocean port. If you want to move a large item to say the central United States, you can ship it by sea, but will still require road transport which adds cost.
I live next to a large air distribution center, which is busy and i often see 747 cargo aircraft and even large Russian built aircraft such as the impressive Antonov-225, so to suggest there is no market is rather short sighted