The number of girls rushing is cyclical ... it depends on the political and social currents. That's why so many chapters closed in the 1960s; there were generally not enough rushees to sustain as many chapters as were on most campuses.
But quota is based on the number of girls rushing near the end of rush, so if half as many girls rush as usual, quota is half as much, and in theory most chapters should still make quota - although the entire system will suffer. Any of several things could be happening to make many chapters fall short of quota:
1) Getting into the "right" chapter is becoming more important; girls will not pledge at all rather than pledge what is a "lesser" sorority in their mind.
2) Girls who aren't traditionally considered good rush candidates are rushing. However, you think they'd get cut early enough on that it wouldn't affect quota.
3) Sororities are cutting too hard, harder than their return rates say they should.
4) Girls are getting turned off by Greek life altogether late in the rush process and not bidding or skipping preference.
5) Several chapters went psycho over the summer after being kidnapped by aliens and were suddenly undesirable.
If it's 3, it's easy to fix. I doubt 4 is happening without at least a little 1 happening, too. (And I really doubt aliens are roaming campus!)
Quota going down all over the country suggests the cyclical popularity of sororities is going down again. Chapters being less likely to make quota means something is broken _during_ the rush process.
