I always find the empty stadium line an odd one; it's not like Saints, Leicester or any other Premiership club are selling out the equivalent of Anfield or Old Trafford, nor does a bigger stadium/higher attendance lead to good performances on the pitch or trophies.Sarries did a brilliant job at building rivalries that weren't there before. This meant more away fans coming to their empty stadium. Their marketing in general has appeared to be brilliant as well as their match day experience.
But I'm still not sure what it has done to their actual fan base. Have there increased their numbers dramatically, I have no idea.
Maybe it's all worked for them.