I'm not sure what other options have been considered (by would-be market entrants), but OutSail appears to be the first company that is attempting to package a sail into a 'box'. Some other companies have made devices like kites which were relatively vessel-type agnostic.

I think one of our main innovations is how to make a very tall and rigid sail without a rigid mast. But you're right, once we figured out how we can roll up a 60m sail into a small package it was obvious to put it in a cargo container.