In the worst case, it would be free to open source the server code. Companies can just do that, and the community can take it from there. I think SKG even allows releasing just a binary in their proposition.
Either way, keeping NPCs entertaining or realistic enpugh to substitute other players is also something that SKG says it’s not asking for. Even if there aren’t other players, being able to enter the world should be enough to consider the game playable.