The elite private colleges are built around the need to bring in a majority of students who are full-pay or close to full pay. As college COA has skyrocketed, the cutoff for “full pay” means that the student body as a whole grows ever-more affluent, and that close-to-full pay group becomes comprised of many students whose families would have been full pay in the recent past.
Harvard is known to have among the most generous need-based financial aid practices of all colleges, but the Common Data Set for 2017-2018 shows a COA of $68,580. Roughly 55% of enrolling freshman received need-based aid, with average grant aid of $53,120-- which is $15,460 below the COA. Given that Harvard also advertises that " if your family earns less than $65,000 per year, your parents pay nothing for you to attend Harvard." --there must be a considerable number of families who earn considerably more than that to counter-balance the students receiving full-ride level grants. I can’t tell from the numbers how many that would be, but I think that it would be fair to assume that a significant fraction of financial aid recipients are receiving grant aid of less than $18K/year – or an expected family contribution of $50K or more-- which would still be cost-prohibitive for most middle-class families.
So yes, the system advantages the advantaged. It is built that way. Harvard may very well be more generous than most, but part of that generosity lies in financial aid policies that direct a significant portion of need-based funds to families who would be considered advantaged in any other setting. And that is one way that holistic admission works – all of those fuzzy factors that are assigned numbers are also a way to assure that Harvard continues to weight its class with the requisite number of the offspring of wealthy parents to assure that the bills get paid in the way the people who manage the finances want.