[Kevin]

It seems to me that if all but say one organization on campus are constantly hitting quota that NPC should mandate that a new group be allowed to colonize.

We have just that problem at a university I am close with. There is one NPC group that suffered a pretty major scandal that resulted in around half of their chapter being expelled. They never recovered and to this day have not once gotten even close to hitting quota (although I guess their numbers are strong enough to justify their continued existance to their HQ).

While all of the other sororities are at the maximum (some over) in terms of membership, this group hovers around 18-30 members.

Quality girls go bidless every year when there could easily be two or three other groups replacing (or supplementing). Once a house earns a certain reputation, it's very difficult to cast it off. Especially in the NPC system.