Keep in mind though, there is a huge ammount of real-life maritime professionals that play this game.
And one of the two organisations in question do things that most real mariners would never agree with, as it is not good/smart seamanship and even puts ships and crew at great risk, on both sides of the fence.
So as such, it might not sell very well. And if you knew how much time and money it costs to develop a ship and put it up for sale in the shipyard, then you can imagine that you have to have a certain return on it. And you have to feel certain beforehand that it will pay for it's own development and then make some profit too.
If it doesn't, it's not a smart move, business wise. And in the end, everyone needs to pay their rent and eat their dinner. I personally would think more money would be made by putting ships on the shipyard that speak to a much broader audience, with more versatility and more revolving around the maritime sector as far as cargo ships and such go.
And keep in mind, you can't really do anything with a Sea Shepard vessel that you can't already do with a Greenpeace vessel. So it would not make for really radically different mission ideas. Except for those that are so much into the environmental issues that they'd make that distinction. And alas, that's only a very small part of the end user group.
I bet most sailors and skippers here would opt for cargo vessels of many kinds, different ferries, inland shipping, and such.
So from that standpoint, I don't think it would happen easily either.
Regards,
Fred