To me, the most valuable benefit to attending an Ivy Plus school, assuming it is affordable to your family, is the vastly improved odds it enables you to reach “high ambition” or “fat tail” outcomes, whether defined by reaching the top of the earnings distribution or other non-monetary measures such as getting into elite graduate schools, attaining positions of great influence (leading jurists, politicians, scientists, journalists, etc.), or working at a prestigious firm.
So if you are a “high ambition” 18 year old, then attending an Ivy Plus can really help you with your ambitions. And I have rarely met a smart 18 year old kid WITHOUT high ambitions for their own life. Thus to say to this 18 year old “well, the odds are that most Ivy Plus graduates will never achieve those fat tail ambitions and therefore you shouldn’t believe your Ivy Plus degree will end up meaningfully different than one from your public state flagship school” is an argument I find unnecessarily cynical.