They actually kind of have... the crew on a big ship do very little “shopping” and a hell of a lot of maintenance. The open sea is a very hostile place and most of the work involved is keeping the ship healthy in that environment.

Agreed. Nowadays the majority of the crew's time is spent either doing maintenance or filling out paperwork to satisfy regulatory requirements - very little involvement with cargo operations (w/ the exception of some specialty liquid cargoes)

I've never heard any one classify maritime shipping as high margin. Having spent over a decade in both ocean and inland waterways operations, my experience has suggested more on the order of 5-10% net margin at best

Margins are high because there are A LOT of risks, starting from superexpensive vehicles and equipment which is never evenly loaded, and ending with bureaucracy, incredibly punishing contracts and weather.

Flexport? Or do you mean a different angle of automate?

Flexport do freight forwarding which is the organising of getting cargo from one place to another, not the actual shipping.