If a school is looking to start Greek life, transition locals to nationals, or needs 2-3 groups at once, the smaller groups could come in and say "if you choose (example) the ASA, AST and TPA combo platter, not only will the sororities be supported by their own nationals, they will work together as a cohesive unit."
Plus as far as Big 10 type schools, if 2 sororities went in together with the INTENTION of being smaller groups, it could be positive, for the groups and the school. Not everyone wants to be in a group with 200 people, yet even a smaller chapter at a bigger school could be larger than some of these groups' average chapters.
I hope this makes sense, somewhat
