PR machines or legit supremacy?

I see all of these rankings where it seems like there are those two sororities that are undeniably agreed to be at the top and I’m genuinely curious if that isn’t just all self-hype or coasting on the past? When I look at the social media for so-called mid or lower tier sororities, I see lots of cute girls. I’ll give PiPhi as an example. It’s full of very pretty, well-dressed, athletic girls who look like they are having fun and have a strong sisterhood and it looks like a ton of them are on the lacrosse team—I guess I just don’t get what makes them “worse” or “lower” than kappa or theta. So….what makes those two so much better or so much stronger than the rest? I know that PiPhi in the middle but even if you drop down lower to Zeta or ChiO I still see cute involved girls…it’s just confusing and it makes me wonder if it really isn’t just people that are in those top two tiers in the equivalent frats acting like their own hype people and everyone else just buying into it.