My guess is the sub launch is the cheapest option. It's a Russian sub and they've been selling off a lot of their old military capability. The first launch I mentioned was also from a Russian sub and it failed because of the upper stage seperation failure. You get what you pay for I guess. I wish them all the luck in the world however.
That's a good hypothesis, I'd buy that. I wonder why we're not using similar launch vehicles?
I think we could learn a lot from watching how this pans out, not just whether the sail works or not, but how private individuals can get things into space. It should be an interesting exercise.