I've only been around for 2 years, but to me, things are going down. When I joined, we really needed new girls, and got 12 new members with my class. That brought the sorority total up to 32 I think (quota is 40). We initiated 21 girls total that year. We were really proud of what we had accomplished. Last year we initiated only 8. This semester we actually initiated 7, but we worked our tail off. We're not losing any seniors next semester (lost 4 this semester to graduation/transferring, but one was alumni anyway), so that should be good, but we will be losing 18 girls within the next year and a half. We got ONE girl during formal recruitment, and only 5 girls total went to Pref Night. Major ouch.
I think queequek has a point. People try to pride themselves on being "independent" and I think people think they're "too good" to go Greek. They've bought into the lies that we choose their friends and tell them what to do.
And in all honesty, I've noticed a lot of people are cheap. Yes, college is getting more and more expensive, so that is probably a big part of it. But I have a hard time getting some of my friends to go out to see a damn movie because they're always complaining that they're broke (maybe if they quit buying so much damn alcohol). I will spend my money for entertainment where it's worthwhile, because I don't like sitting in front of the TV or computer all day.
Maybe it's also because I go to an engineering school and we're all nerds that don't know how to socialize.