is it true ppl drop jr/sr year?

This is common at other schools, between trying to get internships and keep grades up many choose to drop their sorority. Would you say this is relatively common at USC? Only asking bc from the outside looking in, it seems that many choose to be in Greek life all 4 years bc the high costs/time consumption due to social obligations doesn't overwhelm "rich kids" and most likely won't affect their lives much