I fear that without the constant input of an admin like Spazzy, this will never going to happen naturally. The Rheinland playerbase is just too small. It requires players to be logged constantly in Rheinland on both side like they would be if it was Liberty. People just do not log their Rheinland ship and patrol with it. If they see something happening in Rheinland, they will, but otherwise, they just don't. Like in Kusari.
In my opinion, only an inter-house war can be a viable solution.