why do people say chi o declining?

Every house has great girls.

XO is declining because they are very strict on who they take. You must be a legacy and from a certain home town. They don't pick the best girls, they just pick "inbreeds" if you want to call them them.

Sure they some top tier level girls, but they also have basically theta type girls who just have happen to have ole miss XO mom's

How is that different from the other top tiers - from what I've seen, that's how it works with all of them. They get both top girls and some legacies.

Chi-O does have smart, cute and involved girls and they are still a really good sorority. However they tend to be exclusive to a very specific demographic which has somewhat isolated them. It really has become basically a 13th grade of a couple of high schools. Nothing wrong with that if that is what they want, but it's hard to hang on to top tier when everyone knows the only reason you're in Chi-O is because you attended high school with everyone else, not much challenge to that.