1951 Admission Boom to the NPC

[AOII Angel]

My guess would be, since you probably won't be able to find an answer written down somewhere, is that NPC status was desired but not everyone could fulfill the requirements of membership, i.e. chapters only at 4 year institutions, no religious requirements or affiliations, etc. I'm sure that a lot of these groups were hesitent to join and give up some of its chapters and traditions until it became necessary for survival.