in reference to the Lions, it's more or less the talent they are brining through and/or have. Force have a host of wallabies and the Rebels have a few good young players (Jones, Pyle, Kingi ect). The Lions on the other hand really dont have any Springbok contenders, with their best players (such as Taute, Strauss) not having a shot at the Bok squad.
Attendance figures is also a bit off. The two Australian sides get pretty sizeable crowds considering they are in AFL dominated cities. Whilst the Lions crowds always look pretty empty (don't have stats).
All three teams are crap, but it seems the Lions are just really doing nothing for anyone right now, surley they will be replaced for the Southern Kings, whether they finish 5th in SA or not.