[academia_hack]

Really good point. I think at a macro level it makes a lot of sense to do that and if Harvard were a state run institution the government should definitely try to share the benefit. To some extent this is what the use of national entrance exams in many countries (e.g. China, India, Kenya) do, with varying degrees of success.

The problem is, Harvard's incentive is to make a university which is best for its students - not society as a whole. They'd rather scoop up the cream of the crop in terms of affluence+intelligence and then leave the dregs for everyone else. Legacy admits are one tool they use to do that.

I sort of suspect the abolition of SATs serves a similar goal, where a university class can be curated on more than intellectual merit without articles like OP's getting published calling them out for it and the equity arguments universities have made for doing so are either facetious or misguided.