Believe it or not a larger percentage of students at an IVY (or otherwise notable university say Stanford) have busted their ass to get into that school and not coasted 'oh I don't want to work that hard'. Absolutely there are people who have been admitted that have not (family, money, legacy whatever). Just the same there are the same type of students who have gone to a non notable school that may have been Ivy material and not gotten admitted for various reasons (didn't care, couldn't afford, family, whatever).
The thing is about the student body at a top school (IVY or notable again) is the percentage and general feel of the student body that fits the 'busted their ass to get to that school' instead of not caring that much. And really living working and dreaming about going to the top school including but not limited to sacrifices that they might have made.